BMC Oral Health

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Illustrations of posterior restorations included in the study with the correspondent assessments (scores) and treatment decisions.*Note: NA = not applicable; marginal staining was not assessed on amalgam restorations
Description of scores of FDI subcategories used to assess the restoration of this study
The relationship among treatment decisions indicated for assessment restorations comparing CARS and FDI criteria
Article
Background This cross-sectional study aimed to compare two clinical approaches based on visual criteria for secondary caries assessments and treatment decisions in permanent posterior teeth. Methods The two clinical visual criteria tested for the assessments of restored teeth were: FDI criteria—based on the caries presence, marginal adaptation and staining criteria, adapted from the FDI (International Dental Federation) criteria and CARS criteria—"Caries Associated with Restorations or Sealants" (CARS) criteria described by the International Caries Classification and Management System. Adults were randomized according to the criteria. One calibrated examiner assessed the restorations and assigned the treatment according to the criteria. The primary outcome was replacement indication. Results A total of 185 patients were included, totalling 718 restorations. The strongest correlation founded between the methods was for the presence of caries lesions (Rho = 0.829). A moderate correlation (Rho = 0.420) was founded between the treatment decisions proposed by the CARS and by the FDI criteria. The multilevel regression analysis showed that the FDI criteria indicated five times more replacements when compared to the CARS (< 0.001). Also, using the FDI criteria restorations were 2.7 times more related to caries around restorations (p < 0.001) compared to the other criterion. Conclusions The visual criteria used on the restoration's assessment directly influences the treatment decision to intervene or not on the restoration. The use of a minimally invasive based approach for assessing secondary caries may prevent overtreatment.
 
Article
  • Nduguyu KerreNduguyu Kerre
  • James Lwanga NgesaJames Lwanga Ngesa
  • Peter Ng’ang’aPeter Ng’ang’a
  • [...]
  • Ana Lucia SeminarioAna Lucia Seminario
Background The Tanaka and Johnson equation is commonly used in mixed dentition analysis. However, the analysis is based on a Caucasian population making clinical decisions challenging when used in different ethnic groups. This study developed a prediction equation based on a Kenyan population. Design A descriptive cross-sectional study done in 68 13–17 years old Kenyans of African descent in two boarding secondary schools. Alginate impressions were taken, study models obtained, and mesiodistal tooth-widths measured on upper and lower study models from the first molar to the contralateral first molar. Descriptive statistics, paired t-tests and independent t-tests were conducted and Pearson product-moment correlation coefficients calculated (p < 0.05). Results The mean age was 13.78 years (SD ± 0.70), females were 59%. The mesiodistal tooth-widths of the permanent canines and premolars were different between males and females (p ˂ 0.1). The Tanaka and Johnston equation significantly under-estimated the mesiodistal tooth-widths of the permanent canines and premolars (p ˂ 0.05). The addition of lower first permanent molars to the permanent lower incisors provided higher correlation coefficients than the Tanaka Johnston equation. Conclusions A new equation that includes the permanent lower incisors and first permanent molars as predictor teeth seems to be more suitable for mixed dentition analysis for this Kenyan population. A larger study is needed to validate these findings.
 
Preoperative procedure in Group A. a Intraoral examination; b radiographic template; c preoperative CBCT scan and planned implants; d digital design of the implants and prosthesis
Computer-aided manufacturing of the surgical templates and provisional prosthesis. (a, b) Surgical templates; (c, d) Prefabricated provisional prosthesis
Provisional prosthetic protocol. a isolation of the surgical field; b passive fit of the provisional prosthesis; c further modification; d fixation of the provisional prosthesis
Radiographs. a Panoramic radiograph after implant surgery and immediate loading. b Panoramic radiograph at the 6-month follow-up (before definitive restoration): stable marginal bone levels were shown
Postoperative discomfort. a Postoperative pain curves (pain-VAS) over a period of 10 days. b Postoperative swelling curves (swelling-VAS) over a period of 10 days
Article
  • Chaoqun ChenChaoqun Chen
  • Haiyan LaiHaiyan Lai
  • Huiyong ZhuHuiyong Zhu
  • Xinhua GuXinhua Gu
Background To evaluate and compare the clinical outcomes of digitally prefabricated and conventionally fabricated implant-supported full-arch provisional prostheses. Methods In this retrospective study, a total of 39 patients (22 males and 17 females) who underwent implant-supported full-arch rehabilitation using the All-on-4 concept with an immediate loading protocol were included: 20 patients treated with digitally prefabricated provisional prostheses were assigned into Group A, and 19 patients treated with conventionally fabricated provisional prostheses were assigned into Group B. Implant/provisional prosthesis survival rates and complications were reviewed. Marginal bone loss (MBL) was investigated by CBCT. Surgical time, restorative time, and total operative time were analyzed. Postoperative pain and swelling were evaluated with the visual analog scale (VAS). The oral health impact profile (OHIP) questionnaire was administered before and after surgery. Results The implant/provisional prosthesis survival rate was 100%, and complications appeared with low frequency in both groups, while the mean MBL was 0.30 ± 0.29 mm in Group A and 0.31 ± 0.41 mm in Group B after 3~ 6 months ( P > 0.05). The average restorative time in Group A (116.16 ± 16.61 min) was significantly shorter than that in Group B (242.11 ± 30.14 min) ( P < 0.05). Patients in Group A showed lower pain/swelling VAS scores after surgery than Group B ( P < 0.05). Low OHIP scores with high satisfaction with the overall effects were shown in both groups. Conclusion Prefabricated prostheses reduced the prosthetic time and postoperative discomfort in patients whose immediate rehabilitation was based on the All-on-4 concept. This prefabrication technology may be a predictable alternative to improve the short-term clinical outcome of implant-supported full-arch provisional rehabilitation.
 
Study design
Oral photographs of the Marfan syndrome patients. a Oral photographs taken at the first visit in the MFS patients with a planned aortic surgery. b Oral photographs taken at the first visit in the MFS post-surgery group
Comparison of the BOP test results between the study groups at each examination point. a BOP outcomes in the MFS surgery group between examinations. b BOP outcomes in the MFS post-surgery group between examinations. c BOP outcomes in the Healthy group between examinations. d Comparison of the BOP outcomes at the first visit between the groups. e Comparison of the BOP outcomes at the reassessment examinations between the groups. f Comparison of the BOP outcomes at the follow-up examinations between groups. *P < 0.05
Comparison of the PISA test results between the study groups at each examination point. a PISA outcomes in the MFS surgery group between examinations. b PISA outcomes in the MFS post-surgery group between examinations. c PISA outcomes in the Healthy group between examinations. d Comparison of the PISA outcomes at the first visit between the groups. e Comparison of the PISA outcomes at the reassessment examinations between the groups. f Comparison of the PISA outcomes at the follow-up examinations between groups. *P < 0.05
Oral photographs of the MFS surgery subjects
Article
  • Kouta UmezawaKouta Umezawa
  • Takako KajiwaraTakako Kajiwara
  • Kyoko IshiiKyoko Ishii
  • [...]
  • Masahiro SaitoMasahiro Saito
Background Marfan syndrome (MFS) is a systemic disorder of connective tissues caused by insufficient elastic fiber formation that leads to structural weakness and results in various tissue disorders, including cardiovascular and periodontal disease. Notably however, the risk of periodontal disease in MFS patients affected by an aortic aneurysm or dissection has not yet been clarified. Methods We investigated the periodontal condition in the following three groups: MFS patients diagnosed with an aortic aneurysm or dissection with a planned aortic surgery (MFS surgery), MFS patients who had already undergone aortic surgery (MFS post-surgery) and healthy control patients (Healthy). The periodontal condition of all of these patients was evaluated at their first visit, reassessed again at two-month after the first visit, and evaluated again at a six-month follow-up after the reassessment. Results A total of 14 participants, 3 MFS surgery patients, 4 MFS post-surgery patients and 7 healthy control volunteers were examined. Saliva examinations revealed no significant differences between any of the groups at the first visit, reassessment, or follow-up. Interestingly, the MFS surgery cases showed a higher BOP and PISA at the first visit and follow-up compared with the other groups. In contrast, the MFS surgery patients showed an improvement in their LVDd and EF values, both markers of cardiac function, at the reassessment and follow-up compared with the first visit. Conclusions MFS associated with an aortic aneurysm or dissection leads to a higher risk of periodontal disease, indicating the need for more frequent oral hygiene maintenance in these patients. In addition, MFS patients who undergo frequent professional cleaning of their teeth show a lower onset of cardiovascular disease, suggesting that professional oral hygiene in these cases contributes to a healthier condition.
 
Article
Background The Sense of Coherence (SOC) construct has been used worldwide in oral health research, but rigorous factor analyses of the scale are scarce. We aim to test the dimensional structure of the Brazilian short version of the SOC scale with 13 items. Methods This study is a secondary analysis of four independent cross-sectional Brazilian studies on oral health, using the 13-items SOC scale. Sample 1 was conducted on 1760 mothers and 1771 adolescents. Sample 2 comprised 1100 adults. Sample 3 had 720 adults and older individuals. Sample 4 comprised 664 adolescent students. Confirmatory Factor Analysis (CFA) was conducted on sample 1 to compare two models: 3-factor versus 1-factor. Because they were refuted, Exploratory Factor Analysis was implemented in samples 2 and 3. Modified models were tested in sample 4 using CFA. All analyses were conducted with MPlus version 7.11. Results CFA of sample 1 resulted in an unacceptable fit (RMSEA = 0.12;CFI = 0.78; TLI = 0.73; and WRMR = 3.28) for 1-factor model and 3-factor (RMSEA = 0.10; CFI = 0.87; TLI = 0.84; and WRMR = 2.50). The EFA on samples 2 and 3 showed, respectively, two eigenvalues greater than 1 (4.11 and 1.56) and (4.32 and 1.42), but the scale items soc1, soc2 and soc3 formed an uninterpretable second factor. Another CFA, using sample 4, showed acceptable model fit after removing those three items and also soc11 (RMSEA = 0.05; CFI = 0.98; TLI = 0.99; and WRMR = 0.71). Conclusion The results indicate that the SOC-13 scale needs further adjustments. The one-factor model with nine items showed a good statistical fit, but the implications of excluding items should be further investigated, considering the scale's content validity, cross-cultural adaptation and theoretical background.
 
Article
  • Mikio ImaiMikio Imai
  • Yoichiro OginoYoichiro Ogino
  • Hideaki TanakaHideaki Tanaka
  • [...]
  • Takeshi ToyoshimaTakeshi Toyoshima
Background A novel type of implant (Straumann® BLX implant) has been developed for certain stability from the mechanical and biological aspects and is expected for the implant placement in atrophic maxilla with sinus floor elevation (SFE). Purpose The aim of this study was to evaluate the primary stability in the implants with different macrodesigns in an SFE simulated model. Primary stabilities defined as maximum insertion torque (MIT) and implant stability quotient (ISQ) were compared between this novel type of implant and other types. Materials and Methods Five types of Straumann® 10 mm length implants (Standard Plus; SP, Tapered Effect; TE, Bone Level; BL, Bone Level Tapered; BLT and BLX) and two types of Straumann® 6 mm length implants (SP short, BLX short) were used in this study. Each implant was inserted through 5 mm–thick porcine iliac crest blocks (an SFE simulated model). Primary stability was evaluated by using MIT and ISQ. Results The mean value of MIT for BLX group showed significantly higher values than SP, BL (p < 0.01), and TE (p < 0.05) groups. The mean value of ISQ for BLX group was significantly higher than the other groups (p < 0.01). The mean value of MIT and ISQ for BLX and BLX short group were significantly higher than those for SP and SP short group (p < 0.01). Conclusions In an SFE simulated ex vivo model, BLX group showed the highest values. These results suggest that implant selection can play a crucial role in the achievement of primary stability during SFE and simultaneous implant placement.
 
Article
  • Lena CetrelliLena Cetrelli
  • Athanasia BletsaAthanasia Bletsa
  • Anette LundestadAnette Lundestad
  • [...]
  • Marite RyggMarite Rygg
Background Vitamin D deficiency has been associated with autoimmune diseases and oral health. Knowledge about the association between vitamin D status and oral conditions in JIA is limited. We aimed to investigate vitamin D status in a cohort of Norwegian children and adolescents with JIA and possible associations between serum vitamin D levels, clinical indicators of oral health, and JIA disease characteristics. Methods This multi-center, cross-sectional study, included individuals with JIA aged 4–16 years from three geographically spread regions in Norway. Demographic data, age at disease onset, disease duration, JIA category, disease status, medication, and vitamin D intake were registered. One blood sample per individual was analyzed for 25(OH) vitamin D, and the level of insufficiency was defined as < 50 nmol/L. A clinical oral examination was performed applying commonly used indices in epidemiological studies of dental caries, dental erosion, enamel defects, gingival bleeding, and oral hygiene. Serum vitamin D was used as exposure variable in multivariable regression analyses to estimate the associations between insufficient vitamin D level, JIA disease status, and oral conditions, with adjustments for age, sex, geographical region, BMI, seasonal blood sampling, and parental education. Results Among the 223 participants with JIA, 97.3% were Caucasians, 59.2% were girls, and median age was 12.6 years. Median disease duration was 4.6 years, and 44.4% had oligoarticular JIA. Mean serum vitamin D level was 61.4 nmol/L and 29.6% had insufficient levels. Vitamin D levels did not differ between sexes, but between regions, iso-BMI categories, age groups, and seasons for blood sampling. Insufficient vitamin D levels were associated with dentin caries (adjusted OR 2.89, 95% CI 1.43–5.86) and gingival bleeding (adjusted OR 2.36, 95% CI 1.10–5.01). No associations were found with active JIA disease or more severe disease characteristics. Conclusion In our study, nearly 30% had vitamin D insufficiency, with a particularly high prevalence among adolescents. Vitamin D insufficiency was associated with dentin caries and gingival bleeding, but not with JIA disease activity. These results point to the need for a multidisciplinary approach in the follow-up of children with JIA, including an increased focus on vitamin D status and oral health.
 
Representative CBCT images of three-rooted mandibular molars (horizontal view). a A boy aged six years exhibits a three-rooted DMSM at the right side. b A boy aged nine years exhibits bilateral three-rooted DMSMs. c A boy aged seven years exhibits bilateral three-rooted PMFMs. d A girl aged nine years exhibits bilateral three-rooted DMSMs and bilateral three-rooted PMFMs. DMSM is deciduous mandibular second molar and PMFM is permanent mandibular first molar. Arrows indicate the disto-lingual roots
Odontometric measurement of the DB and DL roots of three-rooted deciduous mandibular second molars (DMSMs) and a three-rooted permanent mandibular first molar (PMFM) in the CBCT images (from the adjusted proximal view). a L2 is the vertical length of the DL root; L3 is the level of the distal root furcation (a DMSM). b Angle α is the spreading angle of DL root, and angle β is the spreading angle of DB root (a DMSM). c Angle α is the curvature angle of the DL root measured by Schneider’s method (a DMSM). d Measurement of the angle of root curvature of the DL and DB root by Schneider’s method (a PMFM)
Degrees of root curvatures in the disto-lingual (DL) and disto-buccal (DB) roots of the three-rooted deciduous mandibular second molars (DMSMs) and three-rooted permanent mandibular first molars (PMFMs). Measured by Schneider’s technique. Error bar is SEM, *p < 0.05, **p < 0.01
Article
  • Chengfeng JiangChengfeng Jiang
  • Fan PeiFan Pei
  • Yihan WuYihan Wu
  • [...]
  • Yongchun GuYongchun Gu
Background To investigate the anatomic features of three-rooted deciduous mandibular second molars (DMSMs) in Chinese children by using cone-beam computed tomography (CBCT). Methods A total of 247 CBCT scans of Chinese children were selected and retrospectively analyzed. The occurrence, gender and side predilection of three-rooted DMSMs were examined. The pattern of concurrence of bilateral three-rooted DMSMs, and concurrence of three-rooted DMSM and three-rooted permanent mandibular first molar (PMFM) was analyzed by the concurrence rate and Spearman’s rank correlation test. The geometric parameters of the disto-buccal (DB) and disto-lingual (DL) roots, including the vertical root length, level and angle of distal root furcation, angle of root curvature (by Schneider technique) and the spreading angle, were measured and compared to the three-rooted PMFMs (n = 42) from 100 randomly selected adult subjects. Results The occurrence of three-rooted DMSMs was 24.0% (54/225) calculated by individual, and 18.6% (88/472) by tooth. A significant right-side predilection was detected (23.0% vs 14.2%, p < 0.05), while gender predilection was not detected ( p > 0.05). The bilateral concurrence rate was 49.0%, and Spearman’s correlation test indicated a significant relationship between the antimetric teeth ( rho = 0.609, p < 0.01); whereas a weak but significant co-relationship was detected between the three-rooted DMSM and three-rooted PMFM (right side: concurrence rate = 31.6%, rho = 0.325, p < 0.01; left side: concurrence rate = 23.0%, rho = 0.260, p < 0.01). The length of DL roots in the DMSMs was 7.4 ± 1.5 mm, and the curvature angle was 16.4 ± 11.3 degrees, which was significantly (both p < 0.01) lower than that of the three-rooted PMFMs (root length = 11.0 ± 1.3 mm; degrees of curvature = 34.2 ± 16.1 degrees), whereas the spreading angle of the DL root in DMSMs (34.6 ± 8.4 degrees) was significantly ( p < 0.01) greater than in the PMFMs (26.8 ± 6.5 degrees). Conclusions Three-rooted DMSMs have a high occurrence rate in the Chinese children with a right-side predilection, and they have a weak but statistically significant correlation with three-rooted PMFMs. The DL roots of DMSMs are shorter, less curved, and spreading more widely as compared with those in the three-rooted PMFMs.
 
Article
  • Pawinee WiriyasatiankunPawinee Wiriyasatiankun
  • Rangsima SakoolnamarkaRangsima Sakoolnamarka
  • Panida ThanyasrisungPanida Thanyasrisung
Background It has been claimed that an alkasite restorative material can neutralize acids produced by cariogenic bacteria from released hydrogen ions and enable to remineralization via calcium and fluoride ions. However, there is no evidence to support this assertion. Therefore, the aims of this study were to investigate the effect of the alkasite restorative material on the pH of Streptococcus mutans biofilm and dentin hardness. Methods Streptococcus mutans biofilms were formed on Filtek™ Z350 (FZ, a resin composite) and Cention® N (CN, the alkasite restorative material) and their pH determined after 24 h. Hydroxide, fluoride, and calcium-ions released from the materials were determined at 6 h, 1, 3, 7, 14, and 28 days. Dentin specimens were prepared from 14 human molars and divided into four quadrants. Quadrant 1 was a sound dentin control, quadrants 2–4 were chemically demineralized, and a cylinder of FZ and CN placed on the surfaces of quadrants 2 and 4, respectively. The microhardness of quadrants 1 and 3 were measured at depths of 20, 40, and 60 µm from the occlusal surface, and similarly of quadrants 2 and 4, after 30 days. Independent t-test, Mann–Whitney-U, and repeated-measure-ANOVA were used for data analysis. Results The pH of biofilm on CN (4.45) was significantly higher ( p < 0.05) than that on FZ (4.06). The quantity of all ions released from CN was significantly higher than from FZ. The hardness of demineralized dentin under CN was significantly higher than that of demineralized dentin at all depths, and higher than that of demineralized dentin under FZ at 20 and 40 µm. Conclusions CN released hydroxide, fluoride, and calcium ions, which was associated with raising the biofilm pH and the hardness of demineralized dentin. All results indicated that CN had the potential to reduce the incidence of secondary caries.
 
The points and lines used for measurements. O1 and O2 points: The most lateral points of the ramus, RT: Ramus tangent, PL1: Perpendicular line 1, PL2: Perpendicular line 2, PL3: Perpendicular line 3, CN1 and CN2 points: The intersections between the PL2 and the posterior (CN1) and anterior (CN2) of the condylar neck
Dental panoramic radiograph showing the selection of the condylar area (CA), the condylar perimeter (CP), the condylar height 1 (CH1), the condylar height 2 (CH2), the ramal height (RH) and the total height (CRH = CH2 + RH)
Article
  • Gökhan TürkerGökhan Türker
  • Meriç Öztürk YaşarMeriç Öztürk Yaşar
Background To evaluate condylar morphology, ramus height, and asymmetry indexes in patients with different vertical skeletal patterns and to determine the association between condylar and ramal measurements with the mandibular plane angle. Methods Dental panoramic radiographs of 60 patients with different skeletal patterns were evaluated. According to the cranial base (Sella-Nasion)-mandibular plane (SN-MP) angle, the patients were divided into three groups: normal angle (NA), low angle (LA), and high angle (HA). The condylar area, condylar perimeter, condylar heights, and ramus height were measured, and the asymmetry index value of each measurement was calculated. A one-way analysis of variance as well as a post hoc Tukey and Kruskall-Wallis tests were used to determine intergroup differences. Pearson’s correlation coefficient was used to determine the relationship between all measurements and SN-MP. Results The intergroup comparison of condylar area, condylar perimeter, condylar heights, and ramus height measurements showed that the patients in the LA group have statistically significantly greater values compared to those in the HA group. A statistically significant difference was detected between the NA and LA groups only in the condylar area measurements. There was no statistical difference only in the ramus height measurements between the NA and HA groups. Asymmetry index values of the groups were similar. The negative correlations were found between all measurements and the SN-MP angle. Conclusion HA individuals have lower ramus heights and smaller condylar morphologies than NA and LA individuals. In addition, as the SN-MP angle increases, the condyle dimensions and ramus height decrease, and this is a clinically important finding.
 
The 3D-printed repositioning system for the color measurement. A bovine tooth was embedded in the sample holder (a and b). The size of the measuring window of the sample holder is identical to that of the spectrophotometer (c). The embedded tooth was placed on the lower-left corner of the position locator (d), which was fixed on the spectrophotometer. The sample was held firmly by the movable arm during the color measurement (e)
The workflow of the present study
The average color changes (expressed as △E values) at each experimental time point (HAP 1: the first circle of nano-HAP application; HAP 2: the second circle of nano-HAP application; HAP 3: the third circle of nano-HAP application; HSF: application of hydrodynamic shear force). Lowercase letters indicate the differences between different groups at the same experiment time point. Capital letters indicate the differences of the same group between different experiment time points. Different superscripts indicate groups that statistically differed from any other group (P < 0.05). Same superscripts suggest that groups showed no significant differences (P > 0.05). From a (A) to c (C), the mean value is decreased. * indicates the significant differences between HAP 3 and HSF (P < 0.05)
The nano-HAP adhesion on the enamel surface. a–d: water group; e–h toothpaste without nano-HAP; i–l: 1 wt% nano-HAP toothpaste; m–p: 10 wt% nano-HAP toothpaste. The sample was imaged with FE-SEM at the magnification of 5000 ×
Article
  • Ren ShangRen Shang
  • Dalia KaisarlyDalia Kaisarly
  • Karl-Heinz KunzelmannKarl-Heinz Kunzelmann
Background The aim of this study was to evaluate the postbrushing tooth-whitening effect of toothpaste containing hydroxyapatite nanoparticles (nano-HAPs). The impact of the concentration on the whitening performance of nano-HAP toothpaste was also investigated. Methods Two concentrations of nano-HAP (10 wt% and 1 wt%) were incorporated in nonabrasive toothpastes. Forty bovine incisors were randomly assigned into four groups: 10 wt% nano-HAP, 1 wt% nano-HAP, toothpaste without nano-HAP as a negative control and water as a blank control. Each tooth was treated with the toothpaste three times and hydrodynamic shear force (HSF) once. The teeth surfaces were observed by SEM after each application. Tooth color ( L *, a * and b * values) was measured by a spectrophotometer, and color changes (△ E , △ L , △ a and △ b values ) were calculated. Two-way mixed ANOVA was performed to evaluate the influence of the concentration and repeated application on the tooth-whitening effect of nano-HAP. Results We found that nano-HAP-treated enamel exhibited higher L* values and lower a * and b * values than the control groups ( P < 0.05). The 10 wt% nano-HAP group showed significantly higher △ E values than the 1 wt% nano-HAP group ( P < 0.05). After three applications, the △ E mean value of the 10 wt% nano-HAP group was 4.47. The △ E and △ L values were slightly reduced after HSF ( P < 0.05). For both nano-HAP groups, HAP single crystallites and agglomerates were identified, and their sizes grew with nano-HAP reapplication. Conclusions In conclusion, nano-HAP toothpaste has a satisfying postbrushing whitening effect and good resistance to mechanical forces. The whitening effect seemed to be concentration-dependent.
 
Article
  • Zhang-yan YeZhang-yan Ye
  • Hao YeHao Ye
  • Xi-xi YuXi-xi Yu
  • [...]
  • Xi DingXi Ding
Objective This study aimed to evaluate timing of fixation to retard bone absorption using finite element analysis(FEA). Methods Volunteer CT images were used to construct four models of mandibles with varying degrees of alveolar bone resorption. By simulating occlusal force loading, biomechanical analysis was made on the periodontal membrane, tooth root and surrounding bone (both cancellous and cortical) of mandibular dentition. Results The von Mises stress value of the periodontal structures was positively related with the degree of alveolar bone resorption, and the von Mises stress at the interface between the periodontal membrane and tooth root was increased significantly in moderate to severe periodontitis models. The von Mises stress at the interface between the periodontal cortical bone and cancellous bone was increased significantly in the severe periodontitis model. And the von Mises stress value with oblique loading showed significantly higher than vertical loading. Conclusion Teeth with moderate to severe periodontitis, loosened tooth fixation can be used to retard bone absorption.
 
Article
  • Cong LiCong Li
  • Xiaoyin XuXiaoyin Xu
  • Jing GaoJing Gao
  • [...]
  • Jing ShenJing Shen
Objectives To investigate the feasibility of the 3D printed scaffold for periapical bone defects. Methods In this study, antimicrobial peptide KSL-W-loaded PLGA sustainable-release microspheres (KSL-W@PLGA) were firstly prepared followed by assessing the drug release behavior and bacteriostatic ability against Enterococcus faecalis and Porphyromonas gingivalis . After that, we demonstrated that KSL-W@PLGA/collagen (COL)/silk fibroin (SF)/nano-hydroxyapatite (nHA) (COL/SF/nHA) scaffold via 3D-printing technique exhibited significantly good biocompatibility and osteoconductive property. The scaffold was characterized as to pore size, porosity, water absorption expansion rate and mechanical properties. Moreover, MC3T3-E1 cells were seeded into sterile scaffold materials and investigated by CCK-8, SEM and HE staining. In the animal experiment section, we constructed bone defect models of the mandible and evaluated its effect on bone formation. The Japanese white rabbits were killed at 1 and 2 months after surgery, the cone beam computerized tomography (CBCT) and micro-CT scanning, as well as HE and Masson staining analysis were performed on the samples of the operation area, respectively. Data analysis was done using ANOVA and LSD tests. (α = 0.05). Results We observed that the KSL-W@PLGA sustainable-release microspheres prepared in the experiment were uniform in morphology and could gradually release the antimicrobial peptide (KSL-W), which had a long-term antibacterial effect for at least up to 10 days. HE staining and SEM showed that the scaffold had good biocompatibility, which was conducive to the adhesion and proliferation of MC3T3-E1 cells. The porosity and water absorption of the scaffold were (81.96 ± 1.83)% and (458.29 ± 29.79)%, respectively. Histological and radiographic studies showed that the bone healing efficacy of the scaffold was satisfactory. Conclusions The KSL-W@PLGA/COL/SF/nHA scaffold possessed good biocompatibility and bone repairing ability, and had potential applications in repairing infected bone defects. Clinical significance The 3D printed scaffold not only has an antibacterial effect, but can also promote bone tissue formation, which provides an alternative therapy option in apical periodontitis.
 
Article
Herein, we evaluated the potential therapeutic effects of water extracts from Eucommia on periodontitis in experimental rats. We ligated the maxillary second molars of Sprague–Dawley(SD) rats with 4.0 silk threads and locally smeared Porphyromonas gingivalis ( P. gingivalis ) to induce gingivitis and periodontitis.After the model was successfully established, we exposed the rats to Eucommia water extracts through topical smearing and intragastric administration and evaluated the therapeutic effect of the extracts on gingivitis (for a 2 week treatment period) and periodontitis (over 4 weeks). We analyzed histopathological sections of the periodontal tissue and quantified the alveolar bone resorption levels, molecules related to periodontal oxidative stress, and periodontal inflammatory factors to assess the feasibility of Eucommia in treating gingivitis and periodontitis. We found that damage to the periodontal tissue was reduced after treatment with extracts,indicating that Eucommia has a positive effect in treating gingivitis and periodontitis in experimental rats. These findings are expected to provide the foothold for future research on secondary metabolites derived from Eucommia and guide the development of novel approaches for preventing and treating periodontal disease.
 
Article
Objective: Periodontitis is a chronic inflammatory infectious disease caused by the deposition of dental plaque on the tooth surface, leading to adverse systemic consequences. Accumulating evidence shows that dysregulated microRNAs (miRNAs) are associated with the disease severity of periodontitis. Herein, we report two novel miRNAs, miR-30b-3p and miR-125b-1-3p, in the context of periodontitis and their relationships with disease severity of periodontitis. Methods: The miRNA profiles of gingival crevicular fluid (GCF) samples were used to screen differentially expressed miRNAs (DEmiRNAs) between periodontitis patients and periodontally healthy individuals. Clinical human GCF samples were collected from 80 patients diagnosed with periodontitis (PD +) for the first time and 100 periodontally healthy individuals (PD-). The severity of periodontitis was categorized into mild/moderate (MPD) and severe (SPD) groups. The expressions of miR-30b-3p and miR-125b-1-3p were determined by quantitative real-time PCR. The levels of IL-1β, IL-6, and TNF-α were determined by ELISA methods. Results: We applied GEO2R bioinformatics tool to analyze the raw data of the GSE89081 dataset and identified miR-30b-3p (|logFC|= 1.987) and miR-125b-1-3p (|logFC|= 1.878) between periodontitis patients and periodontally healthy individuals. It was found that PPD, CAL, BOP, and the relative expression levels of miR-30b-3p and miR-125b-1-3p were all higher in the PD + group than the PD- group, in the SPD group than the MPD group (P < 0.05). The periodontitis patients with high-miR-30b-3p expression exhibited increased PPD, CAL, and BOP compared to those low-miR-30b-3p expression, while high-miR-125b-1-3p expression group showed significant differences on PPD and BOP from low-miR-125b-1-3p expression group (P < 0.05). Pearson correlation analysis demonstrated a significantly positive correlation between the levels of inflammatory cytokines, miR-30b-3p expression, and miR-125b-1-3p expression (P < 0.001). Results of ROC curves showed AUC of 0.878 and 0.927, sensitivity of 0.843 and 0.855, and specificity of 0.791 and 0.801, respectively, when miR-30b-3p and miR-125b-1-3p expression levels were used to diagnose periodontitis. Conclusion: These data unveiled that miR-30b-3p and miR-125b-1-3p expressions may be associated with the pathogenesis of periodontitis.
 
Article
Background Oral squamous cell carcinoma (OSCC) is the most frequent tumor of the head and neck. The glycolysis-related genes and immune-related genes have been proven prognostic values in various cancers. Our study aimed to test the prognostic value of glycolysis-immune-related genes in OSCC. Methods Data of OSCC patients were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Enrichment analysis was applied to the glycolysis- and immune-related genes screened by differential expression analysis. Univariate Cox and LASSO Cox analyses were used to filtrate the genes related to the prognosis of OSCC and to construct Risk Score model. Results A Risk Score model was constructed by six glycolysis-immune-related genes (including ALDOC, VEGFA, HRG, PADI3, IGSF11 and MIPOL1). High risk OSCC patients (Risk Score >−0.3075) had significantly worse overall survival than that of low risk patients (Risk Score <−0.3075). Conclusions The Risk Score model constructed basing on 6 glycolysis-immune-related genes was reliable in stratifying OSCC patients with different prognosis.
 
Flow chart of the number of participants included in the study
Article
Background Molar-Incisor Hypomineralization (MIH) is a common oral health condition that can lead to difficulties and complications for both dental professionals and patients. It also has a negative impact on the oral health-related quality of life. The present study aimed to assess the knowledge, clinical experience, and perceived need for training of a group of Egyptian dental students regarding MIH. Methods Paper-based survey administration method was used to collect the responses of dental students regarding their knowledge, clinical experience, and perceived need for training about MIH. The survey consisted of two sections of questions regarding clinical features, etiological factors, prevalence, materials used in treating these teeth, factors affecting the choice of restorative materials, and their preferences regarding clinical training of MIH. Descriptive statistics was used for the data analysis by using SPSS® Statistics Version 26. Results About two-thirds of the respondents were familiar with MIH (69.2%). The vast majority of students (87.8%) had difficulty distinguishing MIH as a developmental defect that differs from other tooth conditions (p < 0.001); most commonly enamel hypoplasia. The most common defects seen by the respondents were yellow/brown opacities (59.1%). Nearly half of the students (45.2%) choose composite resin as the material of choice for the treatment of MIH-affected teeth with aesthetics being the most common factor affecting the selection of restorative material. Almost all students expressed their needs for further clinical training on MIH, especially on treatment aspects. Conclusions Most students are familiar with MIH theoretically. However, there is an urgent need to include clinical training on MIH diagnosis in the practical sessions of pediatric dentistry courses.
 
Article
Background We established a MSBOS for flap reconstruction in oral and maxillofacial cancer patients. Method We enrolled 2080 cases of oral and maxillofacial flap reconstruction from January 1, 2010 to December 31, 2021. Patient data were collected, including age, sex, BMI, preoperative Hb levels, ASA grade, T stage, flap type, tumor location, and bone flap. Scoring criteria were established based on a multivariate model of independent risk variables and their odds ratios. Two flap-type groups were divided into low-risk, intermediate-risk and high-risk groups by the scoring criteria, and analyzed using univariate and multivariate logistic regression. Perioperative transfusion analysis identified independent risk factors at various Hb levels. The cumulative percentage of patients requiring perioperative blood transfusion for each surgical procedure was calculated to establish the MSBOS. Results (1) Regression analysis showed that BMI, tumor T staging, ASA grade, preoperative Hb level (male: Hb < 130 g/L, female: Hb < 120 g/L), and bone flap were independent risk factors for perioperative blood transfusion. (2) Regression analysis showed that independent risk factors for perioperative transfusion included the following: BMI, tumor T3–T4 stage, ASA III, IV grade, and free flap/pediculated flap/bone flap in patients with different Hb levels; T3–T4 stage, ASA grade III–IV in mildly anemic patients; and ASA grade III–IV in moderately anemic patients. (3) A MSBOS was established for flap reconstruction in head and neck cancer patients. Conclusion A MSBOS for head and neck cancer procedures was reduced by approximately 30% perioperative blood preparation while ensuring that clinical blood use standards were met. It help optimize blood inventory, and save blood resources.
 
Photograph of representative specimens from each group
Changes in hue across the red-green axis (Δa)
Changes in hue across the yellow-blue axis (Δb)
Changes in lightness (ΔL)
Article
The long-term color stability and gloss retention of resin composites are among the crucial factors that affect the clinical longevity of esthetic restorations, especially in anterior teeth. This study evaluated the effect of artificial aging by immersion in different storage media and thermocycling on color and gloss of dental single-shade resin composite (Omnichroma) versus multi-shade one (Filtek Z350XT). One hundred resin-composite disc-shaped specimens were used, 50 from each group, Omnichroma and Filtek Z350XT. Ten specimens from each material acted as control group (incubated in saliva). For each material, 40 specimens were divided according to the artificial-aging protocol (immersion at 37 °C for 12 days or thermocycling for 10,000 cycles) and storage media (tea, red wine). Color and gloss were measured before and after artificial aging. Color difference (∆E 00 ) was compared with perceptibility threshold and acceptability threshold. Data were statistically analyzed; independent t test was used to compare results between two tested materials, while two-way ANOVA was used to compare results among the different immersion media within the same material. Artificial aging (immersion or thermocycling) in tea and red wine led to significant color changes and gloss reduction in both materials ( P < 0.05), in contrast to control group. Red wine produced highest color differences. Both dental resin-composites; the single-shade (Omnichroma) and multi-shade (Filtek Z350XT) displayed unacceptable discoloration and gloss reduction after artificial-aging in tea and red-wine by immersion or thermocycling simulating one-year clinical-service.
 
Orientation of an i-CAT image for airway measurement. A Frontal view; B right sagittal view
Landmarks for the pharyngeal airway. A boundary of the OPV; B oropharyngeal airway volume; C boundary of the NPV; D nasopharyngeal airway volume
Schematic diagrams of maxillary arch measurements. A MWM; B IMW and PH; C PA; D MWC and ICW
Differences in the pharyngeal airway and maxillary arch by groups. A Comparison of MB and NB in the skeletal Class I group; B comparison of MB and NB in the skeletal Class II group; C comparison of subjects with skeletal Classes I and II in the MB group; D comparison of skeletal Classes I and II in the NB group
Article
Objective This study aimed to investigate whether the subjects with mouth breathing (MB) or nasal breathing (NB) with different sagittal skeletal patterns showed different maxillary arch and pharyngeal airway characteristics. Methods Cone-beam computed tomography scans from 70 children aged 10 to 12 years with sagittal skeletal Classes I and II were used to measure the pharyngeal airway, maxillary width, palatal area, and height. The independent t-test and the Mann–Whitney U test were used for the intragroup analysis of pharyngeal airway and maxillary arch parameters. Results In the Skeletal Class I group, nasopharyngeal airway volume ( P < 0.01), oropharyngeal airway volume (OPV), and total pharyngeal airway volume (TPV) (all P < 0.001) were significantly greater in subjects with NB than in those with MB. Furthermore, intermolar width, maxillary width at the molars, intercanine width, maxillary width at the canines, and palatal area were significantly larger in subjects with NB than in those with MB (all P < 0.001). In the Skeletal Class II group, OPV, TPV (both P < 0.05) were significantly greater in subjects with NB than in those with MB. No significant differences in pharyngeal airway parameters in the MB group between subjects with Skeletal Class I and those with Skeletal Class II. Conclusion Regardless of sagittal Skeletal Class I or II, the pharyngeal airway and maxillary arch in children with MB differ from those with NB. However, the pharyngeal airway was not significantly different between Skeletal Class I and II in children with MB.
 
The distance between the implant and sinus floor (the distance between A and B) and angle between the implant and sinus floor (∠a). Point A: The highest point where the implant enters the sinus. Line AB: In relation to Point A, we drew a vertical line along the long axis of the implant. Point B: The vertical line intersects with the lateral sinus floor. ∠a: The angle between the implant margin and bone slope of the lateral sinus floor
A-C An implant inserted into the sinus floor resulting in a large amount of new bone formation with a relatively small angle and distance between the implant and sinus floor (A: before the surgery, B: after the surgery, C: after the restoration)
A-C An implant inserted into the sinus floor resulting in a small amount of new bone formation. The adjacent teeth are natural teeth or implants that were placed without transcrestal sinus floor elevation. The angle and distance between the implant and sinus floor are relatively large (A: before the surgery, B: after the surgery, C: after the restoration)
The relationship between implant protrusion length (IPL) and new bone formation (NBF)
A patient who underwent transcrestal sinus floor elevation at two sites, resulting in satisfactory new bone formation. The angle and distance between the implant and lateral wall of the sinus are small. (A: before the surgery, B: after the surgery, C: after the restoration)
Article
Objectives This study aimed to evaluate factors related to new bone formation (NBF) following simultaneous implant placement with transcrestal sinus floor elevation (TSFE). Materials and methods Between 2008 and 2020, 357 implants (276 patients) were placed with TSFE. Clinical and radiographic examinations were performed at the preoperative, postoperative, restoration, and follow-up stages. Marginal bone loss, during healing, and the survival rate were retrospectively analyzed. Results Implant protrusion lengths (IPL: 3–5 mm) significantly influenced NBF during the healing period (P-value = 0.026, Odds Ratio = 1.15, 95% confidence interval = 1.02- 1.30). Bone grafting was correlated with NBF (P-value = 0.001). The distance between the implant and lateral wall of the sinus (mesial: P-value = 0.041, distal: P-value = 0.019, buccal: P-value = 0.032, lingual: P-value = 0.043) and angle between the implant and sinus floor significantly influenced NBF in four directions (mesial: P-value = 0.041, distal: P-value = 0.02, buccal: P-value = 0.047, lingual: P-value = 0.005). Implant shape (cylindrical or conical), perforations, smoking, and diabetes did not significantly affect NBF during the healing period (P > 0.05). Conclusion Increasing the distance and angle between the implant and lateral wall of the sinus floor corresponded with reduced NBF. IPL may be an important factor that should be considered. Clinical relevance Our study analyzed new bone formation following transcrestal sinus floor elevation among patients who underwent this procedure with simultaneous implant placement, several factors (including angle and distance between sinus and lateral wall and implant protrusion length) were included in our study.
 
Schematic draw of the specimens’ treatment and wear measurement. A: Specimen preparation; B: Application of resin coating; C: Immersion in distilled water; D: Chewing simulation; E: Impression taking of the loaded surface; F: Evaluation under stereomicroscope
A replica of specimen surface after chewing simulation was done. This photo was taken under the stereomicroscope
The vertical and volume loss were calculated under the stereomicroscope
Article
Background The effect of nanofilled resin-based coating on the wear resistance of glass ionomer cements (GICs) is still controversial. This study aims to compare the wear resistance of four encapsulated GICs including two conventional and two resin-modified, and to evaluate the effect of G-Coat Plus on the wear resistance of GICs. Methods A total of 80 disk-shaped specimens were prepared from two CGICs (riva self cure (SDI) and Equia Forte Fil (GC) and two RM- GICs (Ketac Nano (3 M/ESPE) and Fuji II LC (GC). The specimens of each material were divided into two groups (n = 10) based on the surface protection: no coating (NC), and coating with G-Coat Plus (GCP). All specimens were then placed in distilled water for 24 h at 37 °C. The specimens were subjected to thermocycling for 120,000 cycles using a chewing simulator. Wear resistance was measured using a specific formula. Data was analyzed using Kruskal–Wallis test. Results There was no significant difference in volume loss (mm ³ ) between coated and uncoated groups for all materials ( P > 0.05). Ketac Nano showed significantly lower volume loss (0.65 ± 0.12) compared to all other groups ( P < 0.05) among uncoated specimen, and significantly lower than Fuji II LC ( P = 0.035) and Equia Forte Fil ( P = 0.040) among coated groups. However, no statically significant difference was observed between volume loss of coated Ketac Nano with that of riva self cure ( P = 0.087). Conclusions Coating with GCP did not affect the wear depth of GICs, and Ketac Nano showed significantly lower volume loss regardless of coating.
 
A PR with acquired measurements. Distance of the root tip of the central incisor (RT1) and second molar (RT7) to the mandibular base, jaw angle (Ang. Mand.), spina nasalis anterior (1), sinus maxillaris (2), caput mandibulae (3), collum mandibulae (4), mandible (5), os hyoideum (6), foramen mentale (7), bony auditory meatus (9), arcus zygomaticus (10), orbita (11), palatum durum (12), septum nasi (13). B LCR with cephalometric parameters. SNA angle, SNB angle, ANB angle, ML-NSL angle, NL-NSL angle, ML-NL angle, NSBa angle, Gn-Go-Ar angle, index = N-Sp′Sp′-Gn×100\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\frac{{N - Sp'}}{{Sp' - Gn}} \times 100$$\end{document}. C Three-dimensional CBCT reconstruction of the chin region showing all measured distances (yellow) and safety margins (red). D Three-dimensional CBCT reconstruction of the right mandibular retromolar region with inferior alveolar nerve (red) and measured dimensions of the bone block. For visualization purposes, only the measurements of the first of three sections was presented. E Coronal CBCT cross-section of the zygomatic alveolar crest with measurements and floor of the maxillary sinus as caudal border of the bone graft (red dotted line)
Scatterplot of Pearson correlation analysis. A Correlation between the ML-NSL angle (LCR; °) and the transverse width of the bony chin (CH3; CBCT; mm). B Correlation between the ML-NSL angle (LCR; °) and the bone height in the chin region (CV3; CBCT; mm). C Correlation between RT1 (PR, mm) and CS4 (CBCT, mm). D Correlation between RT1 (PR, mm) and bone volume of the chin region (CBCT, Vchin, cm³). E Correlation between Gn-Go-Ar angle (LCR, °) and jaw angle (PR, Ang. Mand., °). F Correlation between bone volume of the zygomatic alveolar crest (CBCZ, Vcrista, cm³) and the mandibular retromolar bone volume (CBCT, Vretro, cm³)
Pearson correlation analysis between PR/LCR parameters and CBCT measurements for the chin region
Pearson correlation analysis between PR/LCR parameters and CBCT measurements for the mandibular retromolar region
Pearson correlation analysis between CBCT measurements of the zygomatic alveolar crest and the mandibular retromolar region
Article
Background To test the hypothesis that cephalometric parameters in two-dimensional routine dental radiographs correlate with the bone volume of intraoral bone donor sites. Methods One-hundred and eight radiographs [36 panoramic radiographs (PRs), 36 lateral cephalometric radiographs (LCRs), and 36 cone-beam computed tomography scans (CBCT)] of 36 patients (all three imaging techniques applied according to the needs of treatment planning), were analyzed individually. Cephalometric parameters (PR and LCR) were correlated with the bone volume measurement in three-dimensional CBCT scans in three intraoral donor sites (chin, mandibular retromolar region, and zygomatic alveolar crest). Results The mean bone volumes measured for the chin were (3.10 ± 1.11 cm³ SD), the mandibular retromolar region (1.66 ± 0.54 cm³ SD), and the zygomatic alveolar crest (0.17 ± 0.04 cm³ SD). Cephalometric parameters were significantly correlated (all p -values < 0.05) with the bone volume in the chin and the mandibular retromolar region. The bone volume of the zygomatic alveolar crest exhibited no correlations ( p > 0.05) with cephalometric parameters. However, it was significantly correlated ( p < 0.01) with the mandibular retromolar bone volume. No gender-specific differences ( p > 0.05) were observed concerning bone volumes in all bone harvesting regions. Nevertheless, the male population’s interforaminal distance in the chin region was significantly higher ( p = 0.001). Conclusions PRs and LCRs can be used at the initial stage of peri-implant augmentation planning to deduce conclusions about the bone volume in different intraoral bone donor sites. It can help describe indications and justify additional diagnostic options, such as three-dimensional radiologic techniques.
 
Article
Background Key lncRNAs associated with the malignant progression of oral submucous fibrosis (OSF) to oral squamous cell carcinoma (OSCC) were identified. Methods Key lncRNAs with sequential changes from normal oral mucosa (NOM) to OSF to OSCC were identified based on the GEO database. Kaplan–Meier analysis was used to screen lncRNAs related to OSCC prognosis. Cox regression analysis was used to validate the independent prognostic value. qPCR was used to confirm the expression of the candidate lncRNAs. Gene set enrichment analysis (GSEA), nucleocytoplasmic separation assay, fluorescence in situ hybridization, RNA knockdown, western blot, and cell viability assay were performed to investigate the biological functions of the candidate lncRNA. A nomogram was constructed to quantitatively predict OSCC prognosis based on TCGA. Results Bioinformatics methods indicated that LINC02147 was sequentially downregulated from NOM to OSF to OSCC, as confirmed by clinical tissues and cells. Meanwhile, low LINC02147 expression, as an independent prognostic factor, predicted a poor prognosis for OSCC. GSEA and in vitro studies suggested that low LINC02147 expression promoted OSF malignant progression by promoting cell proliferation and differentiation. A LINC02147 signature-based nomogram successfully quantified each indicator’s contribution to the overall survival of OSCC. Conclusions Low LINC02147 expression promoted OSF malignant progression and predicted poor OSCC prognosis.
 
Patient with bilateral parotid gland tumors (A—right parotid gland tumor, B—left parotid gland tumor)
MRI of bilateral multifocal parotid basal-cell adenomas. The examination shows heterogeneous lesions, with central cystic areas, partially with higher protein content and signs of bleeding, and peripheral solid components (A. T1-weighted axial image, B. T2-weighted axial image, C. T2-weighted coronal image and D. T2-weighted fat-saturated axial image). Solid components of the tumours present vivid enhancement post-gadolinium-based contrast agent (E. contrast-enhanced T1-weighted fat-saturated axial image) and the time-intensity curves obtained on the basis of dynamic contrast-enhanced sequence show a continuous uptake of the contrast agent suggestive of adenomas (F). Tumors did not show signs of diffusion restriction with ADC values of approximately 1.48 × 10⁻³ mm.²/s (G. diffusion-weighted axial image, b 1000, H. ADC map)
Axial T2-weighted MRI image post right total parotidectomy presenting a standard view of the post-operative site with one remaining lesion in the superficial lobe of the left parotid gland
The tumor is surrounded by a fibrous capsule without evidence of invasion, as is characteristic of adenoma. This tumor shows architecture of basal cell adenoma (membranaceous growth pattern)—typical jigsaw puzzle–like islands of basaloid cells, interspersed by occasional vacuolar or small cystic spaces, the cell islands are sharply demarcated from the stroma (H&E staining, × 10)
Article
Background Bilateral parotid gland tumors account for up to 3% of cases. In this group, the vast majority are Warthin’s tumors. However, bilateral presentations of other parotid gland tumor entities is also possible, an example of which is a basal cell adenoma (BCA). Bilateral BCA is extremely rare, which could cause misdiagnosing it as a Warthin tumor. Case presentation The current study reports the unique case of a 48-year-old woman who presented with a 6-month history of slowly growing masses located bilaterally in the parotid region, surgically treated with 5-year follow-up (no recurrence, normal facial nerve function). Magnetic resonance imaging (MRI) revealed three lesions: two in the superficial and deep lobes of the right parotid gland, and one in the superficial lobe of the left parotid gland. A total parotidectomy with facial nerve preservation was performed on the right side, and superficial parotidectomy on the left side 6 months later. Histopathological examination confirmed that all three tumors were BCAs. Molecular analysis didn’t show any strong, potential of unknown clinical significance in the studied sample. Conclusions Multifocal bilateral lesions of the parotid gland are usually Warthin tumors. Detailed preoperative diagnostics including MRI and histopathological examination is essential to avoid misdiagnosing BCA and Warthin tumors. To our best knowledge, no case of synchronous bilateral multifocal basal cell adenomas of the parotid gland has been reported in English literature so far.
 
Article
Background This prospective interventional study aimed to evaluate and analyse the efficacy of rhIL-11 mouthwash compared to Kangfuxin fluid in treatment and blank control in prevention of oral mucositis (OM) in patients receiving chemotherapy. Materials and Methods In total, 50 patients in the treatment group and 62 patients in the prevention group were included. Subsequently, each group was divided into an experimental group and a control group. In the treatment group, the experimental patients received recombinant human interleukin-11 (rhIL-11) mouthwash, whereas the control group received Kangfuxin fluid. In the prevention group, experimental patients still received rhIL-11 mouthwash based on routine oral care, whereas the control group only received routine oral care. Meanwhile, we observed and recorded the efficacy in the treatment group, and the occurrence and grades of OM in the prevention group. Results Through statistical analysis, the results showed that on the seventh day of treatment, the experimental group showed more improvement compared to the control group, and it was statistically significant ( p = 0.032). The average healing time in the experimental group (3.59 ± 1.927 days) was shorter than that in the control group (4.96 ± 2.421 days; p = 0.031). In the prevention group, we observed the incidence of oral mucositis. No significant differences were found in the occurrence and grades of OM in the experimental and control groups ( p = 0.175). Conclusion Our preliminary results indicate that rhIL-11 mouthwash may be a superior option to treat OM, especially in severe cases, compared to Kangfuxin fluid. However, there is no advantage in prevention.
 
Example schematics of question layout for monetary discounting. []: default position of the slider. Top panel: monetary discounting question that combined both delay and probability from Experiment 1. Middle panel: monetary discounting question that presented a choice between monetary gains that change by delay from Experiment 2. Bottom panel: monetary discounting question that presented a choice between monetary losses that change by probability from Experiment 2
Boxplots of delay (left panel) and probability (right) discounting organized by frequency of flossing (x-axes) from Experiment 1. Discounting was calculated using area under the curve with ordinal scaling (AUCord; see text for more details). Higher AUCord values for delay discounting indicate higher preference for the delayed outcome (i.e., lower impulsivity), whereas lower values of AUCord for probability discounting indicate higher preference for the certain option (i.e., lower riskiness). Squares represent the mean AUCord, horizontal black lines represent the median, bottoms and tops of boxes represent the 25th and 75th percentiles respectively, and whiskers are 1.5 times interquartile range. Self-reported flossing frequency; Da: At least once a day. We: At least once a week. Mo: At least once a month. BiAn: At least once in 6 months. An: At least once a year. < An: Less than once a year. *Statistically significant decreases from mean AUCord of daily flossing at α = 0.05. Note that there were no significant increases from daily flossing
Boxplots of delay (left panels) and probability (right panels) discounting organized by frequency of flossing (x-axes) from Experiment 2. Top panels/white boxes indicate discounting for monetary gains, bottom panels/grey boxes indicate discounting for monetary losses. Discounting was calculated using area under the curve with ordinal scaling (AUCord; see text for more details). Higher AUCord values for delay discounting indicate higher preference for the delayed outcome (i.e., lower impulsivity), whereas lower values of AUCord for probability discounting indicate higher preference for the certain option (i.e., lower riskiness). Squares represent the mean AUCord, horizontal black lines represent the median, bottoms and tops of boxes represent the 25th and 75th percentiles respectively, and whiskers are 1.5 times interquartile range. Self-reported flossing frequency; Da: At least once a day. We: At least once a week. Mo: At least once a month. BiAn: At least once in 6 months. An: At least once a year. < An: Less than once a year. *Statistically significant decreases from mean AUCord of daily flossing at α = 0.05. Note that there were no significant increases from daily flossing
Article
Background Interdental cleaning is recommended by dentists but many people do not floss regularly. The health benefits of interdental cleaning are delayed, and sensitivity to delay is an important factor in many health behaviors. Thus, the present studies explore the relationship between frequency of flossing, and sensitivity to delayed and probabilistic outcomes. Method Crowd-sourced subjects were recruited in two studies (n = 584 and n = 321, respectively). In both studies, subjects reported their frequency of flossing and completed delay discounting and probability discounting tasks. Discounting was measured with area under the curve, and linear regression was used to analyze the results. Results Findings show that higher levels of delay discounting were associated with less frequent flossing ( p < 0.001, both studies). In contrast, probability discounting was not significantly associated with flossing frequency ( ns , both studies). Conclusion The findings are consistent with prior studies involving other health behaviors such as attendance at primary care and medication adherence. Results suggest that interventions that reduce delay discounting may help promote regular interdental cleaning, and that delay discounting is a more robust predictor of health behaviors than probability discounting. In addition, interdental cleaning appears to be a reasonable target behavior for evaluating potentially generalizable behavioral health interventions. Thus, interventions that are successful in promoting oral health behaviors should be considered as candidates for evaluation in other health behavior domains.
 
Flow diagram depicting sample numbers
ROC curve for risk predicton model for the 3-year-old cohort
ROC curve for risk predicton model for the 5-year-old cohort
Article
Background: Despite increasing prevalence, age-specific risk predictive models for erosive tooth wear in preschool-age children have not been developed. Identification of at-risk groups and the timely introduction of behavioural change or treatment will stop the progression of erosive wear in the permanent dentition. This study aimed to identify age-specific risk factors for erosive wear. Distinct risk prediction models for 3-year-old and 5-year-old children were developed. Methods: A prospective cohort study included school-based clinical examinations and parent administered questionnaires for consented 3 and 5-year-old healthy children. Calibrated examiners measured the following health parameters under standardised conditions: erosion, using the Basic Erosive Wear Examination Index (BEWE), caries using the International Caries Detection and Assessment System (ICDAS), plaque and calculus according to the British Association for the Study of Community Dentistry (BASCD) scores, dental traumatic injuries and soft tissue lesions, salivary testing and BMI. Other health conditions were collected via a parent-administered questionnaire that explored oral- and general-health. Non parametric tests were utilised to explore the temporal relation of erosion with, demographic factors, oral hygiene habits, general health and dietary habits. Variables showing significance with a difference in BEWE cumulative score over time were utilised to develop two risk prediction models. The models were evaluated by Receiver Operating Characteristics analysis. Results: Risk factors for the 3-year-old cohort (N = 336) included erosive wear (χ2(1, 92) = 12.829, p < 0.001), district (χ2(5, 92) = 17.032, p = 0.004) and family size (χ2(1, 92) = 4.547, p = 0.033). Risk factors for the 5-year-old cohort (N = 441) also included erosive wear (χ2(1, 144) = 4.768, p = 0.029), gender (χ2(1, 144) = 19.399, p < 0.001), consumption of iced tea (χ2(1, 144) = 8.872, p = 0.003) and dry mouth (χ2(1, 144) = 9.598, p = 0.002). Conclusions: Predictive risk factors for 3-year-old children are based on demographic factors and are distinct from those for 5-year-old children based on biological and behavioural factors. Erosive wear is a risk factor for further wear in both age cohorts.
 
Article
Background Regardless of attaining adequate knowledge regarding oral hygiene, physical activity, and healthy eating habits, dental students still face oral health problems. This study was aimed to assess the association of oral hygiene habits, physical activity, and eating habits with the BMI in the dental students. Method This multi centric cross-sectional study was conducted from January to May 2021 in Pakistan. Three hundred and eighty-six study participants enrolled as undergraduate dental students, both males and females, were included in the study. A questionnaire used to gather data, was modified from a study conducted by Jouhar et al. Chi-square testing was used in order to assess the relationship between two categorical variables. Linear regression was performed to assess the association with putative confounders. Statistical significance was considered for p value < 0.05. Results Regarding brushing teeth, 57% of the underweight individuals brushed once daily, 69.8% of the healthy, 79.2% of overweight, and 48% of obese participants brushed twice. Horizontal brushing technique was performed by 50% of the underweight participants, followed by scrub technique. A soft bristled brush was frequently used by underweight (42.9%) and healthy (66%) individuals, while a medium textured bristle brush was used by overweight (62.3%) and obese (54.2%) participants. Majority of the underweight (64.3%), overweight (48.1%), and 45.8% of obese individuals had meals thrice a day, while healthy (62.3%) individuals had meals twice a day. Conclusion This study further intensified the contributing role of having an excessive dietary intake and sugar consumption in causing obesity and dental caries. Findings from the current study, identify a statistically significant relationship that exists between BMI levels with oral hygiene, eating habits and the physical activity.
 
Recommended guidelines for tele-triage categorization and tele-triage decisions based on American Dental Association (ADA) [6], General Dental Council, UK [32], and Centers for Disease Control and Prevention (CDC) [33]
Article
Background: Globally, with the COVID-19 pandemic, dental services were limited to emergency/ urgent conditions and were provided only after tele-triage referral for face-to-face management. However, no previous research explored whether the pain severity (PS) drives the tele-triage decisions. The current study examined the association between PS and tele-triage decision of whether to manage the condition remotely or refer the caller for face-to-face management. Methods: This retrospective cross-sectional study analyzed the PS reported by hotline callers, using numerical rating scale (NRS-11), during the first wave of COVID-19 lockdown (23 March-31 August 2020) and its association with tele-triage decision controlling for age, sex, history of chronic illness, and dental discipline needed. Binomial logistic regression assessed the association between the PS (exposure) and tele-triage decision (outcome). ANOVA compared PS across tele-triage categories, dental history and tentative diagnosis. Results: PS was significantly associated with tele-triage decisions (p < 0.05). An increase in pain score by 1 unit was associated with 1.4 times increased odds of face-face referral (95% CI: 1.26-1.54). Pediatric/ adolescent patients (9-18 years) (odds ratio (OR) = 2.07; 95% CI: 1.07-4.02), history of chronic illness (OR = 2.12; 95% CI:1.28-3.51), need for surgical specialty (OR = 1.93; 95% CI: 1.22-3.04) and orthodontic specialty (OR = 7.02; 95% CI: 3.54-13.87) were independently associated with tele-triage decision. PS was highest for the emergency triage category (8.00 ± 2.83, P < 0.0001), dental history of tooth with cavity or filling (6.65 ± 2.024, P < 0.0001), and the tentative tele-diagnosis of cellulitis (7.75 ± 2.872, P < 0.0001). Conclusions: During COVID-19 pandemic, tele-triage decisions were significantly influenced by patient-reported PS, adjusting for a range of variables. Despite this, referral for face-to-face management was individualized and driven by the tripartite considerations of the reported pain, clinical judgement, and the high transmission characteristics of COVID-19.
 
Predicted satisfaction over time
a Predicted satisfaction in Scotland versus England and Wales over time. b Predicted satisfaction of those who have a degree versus who don’t over time. c Predicted satisfaction of income quartile over time. d Predicted satisfaction of those who are white versus who are not over time
a Predicted satisfaction of those who are over 65 versus those who are not. b Predicted satisfaction of those who are married versus those who are not. c Predicted satisfaction of those who have dependent children in the household versus those who do not. d Predicted satisfaction of those who are male versus female
Article
Background Satisfaction with dental services can provide valuable insights into aspects of quality including access as well as changes in this over time. In the UK publicly funded dental services are ostensibly delivered by private sector general dental practitioners for whom private patients represent an opportunity cost to the provision of care to public patients. This study examined changes in satisfaction as economic circumstances and policy changed in Britain between 1998 and 2019. Methods Data were taken from successive waves of the British Social Attitudes Survey a representative cross-sectional survey of the population between 1998 and 2019. Descriptive statistics and a series of logistic regression analyses were used to examine the relationships between satisfaction and a range of socio-demographic characteristics over time. Results 37,328 usable responses were extracted from the survey spanning 21 years of data. Over the course of the survey approximately 71% of the sample was very satisfied, satisfied or neither satisfied nor dissatisfied with publicly funded dental services. Satisfaction fell at the outset of the study period but rose following the economic downturn from 2008 which coincided with increased use of publicly funded services. Differences were evident in satisfaction between older versus younger respondents, more affluent versus less affluent respondents and better educated versus less well-educated respondents. Satisfaction did not appear to change in response to policy changes. Conclusion Satisfaction is an important outcome of service provision. Policies aiming to improve satisfaction with publicly funded dental care in the UK must take account of the competing demands on dentists’ time from private patients. At times of economic expansion or when supply has been disrupted, these may be particularly acute and require specific interventions to improve access for those who depend on public services.
 
Article
Purpose To analyze the link between individuals with and without migration background and oral health-related quality of life (also stratified by sex). Methods Data in this cross-sectional study were taken from a nationally representative survey (n = 3075, August/September 2021). The Oral Health Impact Profile (OHIP-G5) was used to measure oral health-related quality of life. Two-part models were calculated, adjusting for various covariates. Results Individuals with migration background had lower oral health-related quality of life (total sample, Cohen’s d = − 0.30; in men, d =− 0.44; in women, d =− 0.22). Two-part models also revealed that the migration background was associated with a higher likelihood of OHIP-G5 scores of one or higher (total sample and in both sexes). Moreover, migration background was positively associated with the extent of oral health-related quality of life (conditional on OHIP-G5 scores of one or higher; total sample and in men). Furthermore, regressions showed that migration background was associated with lower oral health-related quality of life (total sample and in both sexes). Conclusions Our study emphasized the link between having a migration background and lower oral health-related quality of life among both women and men. Maintaining oral health among individuals with a migration background is a key challenge. Culturally and socially sensitive actions should provide easy accessible oral health information and preventive measures in order to lower access barriers in dental care for individuals with migration background.
 
Article
Background Dental caries affects the majority of children in Jordan, with some evidence of its prevalence steadily increasing. Previous studies have shown that families struggle to establish good oral health practices. The aim of this study was to evaluate the current oral health status and practices of 6- to7-year-old children in Amman, Jordan.r Methods A cross-sectional cohort study. The sample consisted of 6- to 7-year-old children attending six randomly selected schools in Amman, Jordan. Measures collected were: I) Caries experience (d3mft/D3MFT), II) Oral hygiene, measured using the Simplified Oral Hygiene Index, III) Dietary, toothbrushing, and dental attendance practices, measured using diaries and parental questionnaires, IV) Participants’ basic characteristics: age, education and employment. Data were analysed using SPSS20. Results In total, 942 children were recruited. Four hundred and fifty-seven were boys, 485 were girls. Their average age was 6.5 years. Eighty-nine percent had decay in their primary teeth. Mean d3mft was 5.1(1 (range = 0–12, SD = 2.9). Only 8% of carious teeth were restored. Mean DMFT score was 0.3 (range = 0–4, SD = 0.8). Mean debris score was 1.07 (range = 0–3, SD = 0.37). Children indicated that they brush their teeth 1.6 times a day (range = 0–3, SD = 0.6). The majority (81%) were unsupervised. Sixty-seven percent of parents did not know the appropriate fluoride toothpaste concentration. Children were having 1.5 sugary snacks in-between their meals (Range = 1–6, SD = 1.1). They scored a mean of 2.5 (Range = 0–5.87, SD = 1.7) in sweetened drinks intake (recommended ≤ 1) and 2.8 (Range = 0–18.57, SD = 1.5) in non-core food intake (recommended ≤ 2) on a dietary questionnaire. Most parents (84%) indicated that their child attends the dentist only when in pain, and 18% indicated that their child is extremely afraid of dentists. Only 32% and 18% were familiar with fluoride varnish and fissure sealants, respectively. Regression analysis revealed that debris score and dental attendance were reliable predictors of caries experience. Conclusions Six- to seven-year-old children in Amman, Jordan have a high caries experience. Most show signs of poor oral hygiene, excessive intake of cariogenic foods, and symptomatic dental attendance. Their parents lack knowledge on fluoride varnish and fissure sealants. There is a need for oral health promotion tailored to this cohort's need.
 
An orthopantomogram (OPG) illustrating the method of measurement used in the study. The impacted lower right third molar is classified as class II and level C according to Pell and Gregory's classification. The long axis of the impacted lower left third molar forms a 42° angle with the long axis of the adjacent second molar. Therefore, it is classified as mesioangular according to Winter’s classification
An orthopantomogram (OPG) illustrating the presence of distal caries in both right and left mandibular second molars associated with impacted mandibular third molars
The distribution of impacted lower third molars according to Pell and Gregory and Winter’s classifications
The impaction type of the studied impacted lower third molars according to the Pell and Gregory classification and Winter’s classification
The distribution of impacted lower third molars by sex
Article
Objectives The purpose of this study was to investigate the pattern of mandibular third molar (MTM) impaction and associated carious lesions in adjacent mandibular second molars (MSMs) in a sample of Emirati individuals. Methods This retrospective study assessed 2000 orthopantomograms of Emirati patients who visited the Specialized Fujairah Dental Center between 2015 and 2020. The depth, ramus relation and angulation of the impacted MTMs were assessed according to the Pell and Gregory classification and Winter’s classification. In addition, carious lesions in adjacent MSMs associated with the evaluated parameters were identified. Results A total of 461 (23.05%) of the patients had at least one impacted MTM. The mean age of the study population was 26.24 years. Mesioangular, level B, and class II impactions were the most common, at 47.37% (χ ² = 382.134; p < 0.001), 45.48% (χ ² = 56.889; p < 0.001), and 74.05% (χ ² = 513.099; p < 0.001), respectively. There was a higher percentage of level C impaction among females than among males (χ ² = 19.178; p < 0.001). A total of 126 impacted teeth (18.36%) had associated carious lesions. These carious lesions were predominantly found in teeth with mesioangular impactions (χ ² = 59.430; p < 0.001), level A and B impactions (χ ² = 23.301; p < 0.001), and class II and I impactions (χ ² = 17.918; p = 0.006). Conclusions It is imperative to raise awareness of soft tissue mesioangular-impacted MTMs, as they are the most frequently associated with the development of carious lesions in adjacent MSMs. Approximately one quarter of evaluated Emiratis had at least one impacted MTM, with the most prevalent pattern being class II, level B, and mesioangular impactions. Furthermore, surgical removal is expected to be more challenging for females than for males.
 
Article
Background Oral health-related quality of life, a prominent topic in dentistry, has been studied extensively. However, the comparison between various self-perceived and clinical oral health measures still needs to be explored. The purpose of the current study is; first, to report the self-perceived and clinically examined oral health measures that are associated with the oral impacts on daily performances. Second, to identify the oral health measure that best predicts greater oral impact scores. Third, to investigate the difference in findings related to the disease experience measures and the treatment measures. Methods A cross-sectional study was carried out on children aged 12–14 years. The prevalence, frequency, and oral impact scores of each daily performance were calculated. Thirteen self-perceived OH conditions were assessed. Clinically examined oral health measures included gingival health, oral hygiene status, DMFT, DT, MT, and FT scores and, one or more decay (1 + D), missing (1 + M) and filled (1 + F) teeth. Simple linear and multiple linear regressions were carried out to report the associations. Results At least one oral health impacted daily performance was reported by 40% of the total sample of schoolchildren (N = 700). Based on the magnitude and precision of adjusted regression coefficients (RC), decay severity (DT) was identified as a better predictor of a greater oral impact score with regression coefficient values ranging between 0.3 (social contact) and 2.4 (1 + performance). Contrariwise, MT and FT components of DMFT were associated with lower oral impact scores. The self-perceived measures were also associated with oral impact scores and presented similar findings to that of the clinical oral health measures. Conclusions Untreated decay significantly impacted daily performances, especially eating, sleeping, studying, and social contact. The findings are of importance to public health practitioners for reporting, treating, and preventing oral health problems in children, and eventually contributing to better oral health-related quality of life.
 
Distribution of anatomical lesion site of OSCC
Degree of differentiation of OSCC
Article
Introduction Oral cancer is considered a major global public health problem. The causes of OSCC are tobacco, alcohol, viral infections such as EBV, HPV, and herpes simplex virus, poor oral hygiene (including sharp teeth and decay), ill-fitting denture, ultraviolet (UV) exposure, nutrition, and genetic predisposition. The etiology of oral cancer varies in different populations due to area-specific etiological factors. Objective Finding a correlation of histopathological pattern to the tumor site and habits as an outcome of OSCC. Methods This cross-sectional study was conducted in Karachi, Pakistan. A total of 100 known cases of an oral squamous cell carcinoma were diagnosed with the help of biopsy reports and were examined for histopathologic features, site of the lesion, and risk habits. Results 48 years was the mean age at the time of diagnosis with a distribution of 61% men and 39% women. The frequently affected site was buccal mucosa and the prime risk habit was gutka followed by betel quid. Histologically, the degree of differentiation shows that moderately differentiated OSCC was most commonly present, while the most prevalent histopathological pattern was spindle cell carcinoma. The statistical relation between lesion site and tobacco habits was found to be significant with a p value ( p = 0.01). Conclusion Rates of oral squamous cell carcinoma are higher in males than females with a mean age at the time of diagnosis being less than 50 years. Frequently placing gutka in the buccal vestibule against buccal mucosa is responsible to make buccal mucosa the most common tumor site. This study provides baseline information regarding habits.
 
a Example of neutral canine relationship (Class I) and corresponding maxillary central incisor; b Example of mesial canine relationship (Class III) and corresponding maxillary central incisor
a Determination of panoramic curve after head position reorientation; b Observation plane (blue): mid-sagittal plane passes through chosen tooth’s long axis which was perpendicular to panoramic curve (yellow)
a Measurements of bone thickness at different aspects; b Measuring the sagittal angulation of the maxillary central incisor based on the tooth axis and the axis of its respective alveolar process. MBT, mid-root buccal thickness; MPT, mid-root palatal thickness; ABT, apical buccal thickness; APT, apical palatal thickness
Illustration of the frequency distributions of MBT, MPT, ABT, APT. MBT, mid-root buccal thickness; MPT, mid-root palatal thickness; ABT, apical buccal thickness; APT, apical palatal thickness. *Statistically significant difference between Class I and III canine relationships (p < 0.05)
Illustration of the frequency distribution of sagittal angulation between the long axes of tooth and its associated alveolar bone. *Statistically significant difference between Class I and III canine relationships (p < 0.05)
Article
Background: Canine relationship is a key reference identifying anterior malocclusion and an important implication for evaluating preimplantation bone morphology at maxillary esthetic zone. This study aimed to compare the differences of maxillary central incisor-related measurements (alveolar bone thickness and tooth sagittal angulation) between Class I and Class III canine relationship and further explore the risk factors for immediate implant placement in the anterior maxilla based on cone beam computed tomography (CBCT) data. Methods: CBCT digital imaging and communications in medicine (DICOM) files of 107 patients (54 with Class I canine relationship and 53 with Class III canine relationship) were collected and the alveolar bone thickness at mid-root (mid-root buccal thickness/MBT; palatal/MPT), apical regions (apical buccal thickness/ABT; palatal/APT) and sagittal angulation (SA) of the maxillary central incisor at the examined side were measured on the mid-sagittal observation plane. Descriptive statistical analysis and frequency distributions of the measurements based on Class I or Class III canine relationship were established. Statistical analyses were performed using Fisher's exact test, independent samples t test and Pearson correlation test with the significance level set at p < 0.05. Results: The frequency distributions of maxillary central incisors' MPT, ABT, APT and SA showed significant differences between Class I and Class III canine relationships (p = 0.030, 0.024, 0.000 and 0.000, respectively). MPT (2.48 ± 0.88 mm vs. 3.01 ± 1.04 mm, p = 0.005), APT (6.79 ± 1.65 mm vs. 8.47 ± 1.93 mm, p = 0.000) and SA (12.23 ± 5.62° vs. 16.42 ± 4.49°, p = 0.000) were significantly smaller in patients with Class III canine relationship. Moreover, SA showed a strong positive correlation with APT (R = 0.723, p = 0.000) and a moderate negative correlation with ABT (R = - 0.554, p = 0.000). Conclusions: In populations with Class III canine relationship, maxillary central incisors were significantly more labially inclined and have a thinner palatal bone plate at the apex compared with Class I relationship. Clinicians should avoid palatal perforation during immediate implantation at sites of originally protrusive maxillary incisors.
 
The representative 3-D models of round and oval canal in mandibular incisors. A Oval and round canal model before root canal preparation. B Oval and round canal after root canal preparation. C Matched and superimposed root canal indicated the untouched surface (red) and touched surface (green) from mesio-distal view. D Matched and superimposed root canal indicated the alteration of canal geometry after preparation, pre-operative canals (red) and the post-operative canals (green) from buccal-lingual view. E Cross-sectional views of the coronal, middle and apical thirds of before and after root canal preparation
Percentage change of the root canal morphological parameters after root canal preparation. The percentage change of UCW (A), SMI (B), Formfactor (C), Roundness (D), AR (E), major diameter (F), minor diameter (G), canal area (H) and canal volume (I) were evaluated in both oval canal group and round canal group in different regions (coronal, middle and apical third). *indicates P < 0.05, **indicates P < 0.01, ***indicates P < 0.001. UCW: Untouched canal wall. SMI: Structure model index. AR: aspect ratio. Δ%: the percentage change of the canal morphological parameters
Color-coded 3D distribution of dentin thickness. Color-coded 3D distribution of dentin thickness between internal canal surface to external root surface in coronal 2/3 of the mandibular incisors on different surface before (pre-) and after root canal preparation (post-) were visualized. (A1, B1, C1, D1) represent the general view of the thickness distribution from 45° view. The thickness distribution of root 2/3 on the buccal root surface (A2, B2, C2, D2), the lingual root surface (A3, B3, C3, D3), and the proximal root surface (A4, B4, C4, D4). Pre-: Pre-operative model. Post-: Post-operative model
Article
Background: Relatively high incidence of single canals with oval or round shape were observed in human mandibular incisors. In order to investigate the influence of the root canal morphology on root canal preparation, the shaping outcome of ProTaper NEXT in oval and round canals of mandibular incisors were evaluated by using micro-computed tomography (micro-CT) analysis. Methods: This experiment was approved by the School Medical Ethics Committee. The sample size calculation was conducted using G*Power software. Intact mandibular incisors with a single canal were selected. Oval canals (2 < aspect ratio (AR) ≤ 4) and round canals (AR ≤ 2) were pair-matched according to canal length, and assigned to two experimental groups (13 per group). ProTaper NEXT was used for root canal preparation for both groups. Untouched canal wall (UCW), root canal morphological parameters and three-dimensional (3D) dentin thickness were evaluated in the entire root canal and each canal third after micro-CT scanning. Statistical analysis: Data were collected and analyzed with Mann-Whitney test and Friedman test using SPSS statistics software 25 (P < 0.05). Additionally, correlations of UCW area with canal morphological parameters were also investigated. Results: After root canal preparation, no significant difference was observed in all analyzed parameters in the apical third between oval and round canal groups (P > 0.05). In the coronal two thirds of the canal, the post-operative structure model index (SMI), form factor and roundness were significantly increased, while the AR was significantly decreased in both groups (P < 0.05). In addition, in the coronal two thirds, significantly more UCW and higher UCWΔ% was observed in oval canal group (P < 0.05). Furthermore, UCW correlated very strongly to canal major diameter (0.924) and initial volume (0.938), and strongly to canal form factor (- 0.724), minor diameter (0.799) and canal area (0.882). Proximal dentin wall was associated with significantly thinner pre-operative dentin thickness and higher amount of dentin removal after root canal preparation in both oval and round canal groups. Conclusions: (1) Both types of canals were more conical after root canal preparation, but oval root canals tend to leave more UCW area than round canals in the coronal two thirds of mandibular incisors, which contributes to the challenge for endodontic infection control. (2) Root canal preparation usually results in excessive dentin removal in the proximal dentin wall comparing with buccal and lingual walls in both types of canals of mandibular incisors.
 
Identification of human periodontal ligament stem cells (PDLSCs). a Immunofluorescence showed that PDLSCs used in this study express CD146 and CD105, but negative for CD45. Jurkat cells were positive for CD45. Scale bars, 100 μM. b Flow cytometry showed that human PDLSCs exhibited the expression of cell surface markers, including CD146 (91.8%), CD105 (87.6%) and CD45 (0.05%). Isotype control was used in this experiment. Jurkat cells exhibited the expression of CD45 (82.5%). c Alizarin red staining assay was performed to prove the mineralized nodules formation after 14-days osteogenic induction. Scale bars, 100 μm. d The cellular Oil red O-positive lipid clusters were stained after 21-days adipogenic induction. Scale bars, 50 μm
Sodium butyrate (NaB) reduced the viability of periodontal ligament stem cells (PDLSCs). a, The cell proliferation curve of PDLSCs was depicted after the treatment of NaB for 24, 48, and 72 h. b, The absorbance values showed that NaB inhibited PDLSC proliferation in a dose- and time-dependent manner. c, d Flow cytometry showed that 5 mM NaB induced human PDLSC apoptosis in 24 and 72 h. Error bars represent the standard deviation (n = 3). *p < 0.05, **p < 0.01, using Student’s t test and one-way ANOVA
Sodium butyrate (NaB) decreased the osteogenic capacity of periodontal ligament stem cells (PDLSCs). a Evaluation of alkaline phosphatase (ALP) activity 5 days after osteogenic induction indicated that 1 mM NaB decreased ALP activity in PDLSCs. b, c Alizarin red staining assay and cetylpyridinium chloride assay performed 14 days after induction showed that 1 mM NaB decreased the formation of mineralized nodules in PDLSCs. d–g Following 7 days of osteogenic induction, RT-PCR showed that 1 mM NaB downregulated Runx2, OSX, OCN, and OPN. h Western blotting showed that 1 mM NaB reduced the protein expression of Runx2, OSX, OCN, OPN, Smad1 and p-Smad1/5/8. i Following 14 days of osteogenic induction, RT-PCR showed that 0.1 mM and 1 mM NaB downregulated OCN. j Western blotting and densitometric analysis showed that 0.1 mM and 1 mM NaB reduced the protein expression of OCN. The length of the blots was appropriate in the manuscript. Error bars represent the standard deviation (n = 3). *p < 0.05, **p < 0.01, using one-way ANOVA
Sodium butyrate (NaB) inhibited periodontal ligament stem cell (PDLSC) osteogenesis by downregulating Smad1. a Free fatty acid receptor 2 (FFAR2) antagonist (GLPG0974) slightly increased alkaline phosphatase (ALP) activity in NaB-treated cells (compared to the NaB group). b, c GLPG0974 significantly reversed the NaB-mediated inhibition of mineralized nodule formation and the expression of Runx2 and OPN. d–f FFAR2 agonist (4-CMTB) decreased ALP activity, mineralized nodule formation and the expression of Runx2, OCN and OPN in NaB-treated cells. g, h Western blotting and densitometric analysis showed that GLPG0974 reversed the NaB-mediated reduction of Smad1 and p-Smad1/5/8 (compared to the NaB group), while 4-CMTB reduced the the expression of Smad1 and p-Smad1/5/8. The length of the blots was appropriate in the manuscript. i NaB decreased the expression of Smad1 by activating FFAR2, thus reducing the translocation of the p-Smad1/5/8-Smad4 complex into the nucleus, downregulating the expression of Runx2 and OSX, and inhibiting the osteogenic differentiation of PDLSCs. Error bars represent the standard deviation (n = 3). *p < 0.05, **p < 0.01, using one-way ANOVA
Sodium butyrate (NaB) decreased human periodontal ligament stem cell-mediated bone formation in nude mice. a H&E staining revealed less bone-like tissue formation around HA/TCP in the NaB-treated group compared to the control. b Quantitative measurement of the mineralization area revealed less bone-like tissue formation in the NaB-treated group than in the control. Red lines represent bone-like tissue; HA = HA/TCP; CT = connective tissue. Scale bars, 100 μM. Error bars represent the standard deviation (n = 3). *p < 0.05, **p < 0.01, using Student’s t test
Article
Background Butyrate is a major subgingival microbial metabolite that is closely related to periodontal disease. It affects the proliferation and differentiation of mesenchymal stem cells. However, the mechanisms by which butyrate affects the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) remain unclear. Here, we investigated the effect of sodium butyrate (NaB) on the osteogenic differentiation of human PDLSCs. Methods PDLSCs were isolated from human periodontal ligaments and treated with various concentrations of NaB in vitro. The cell counting kit-8 assay and flow cytometric analysis were used to assess cell viability. The osteogenic differentiation capabilities of PDLSCs were evaluated using the alkaline phosphatase activity assay, alizarin red staining, RT-PCR, western blotting and in vivo transplantation. Results NaB decreased PDLSC proliferation and induced apoptosis in a dose- and time-depend manner. Additionally, 1 mM NaB reduced alkaline phosphatase activity, mineralization ability, and the expression of osteogenic differentiation-related genes and proteins. Treatment with a free fatty acids receptor 2 (FFAR2) antagonist and agonist indicated that NaB inhibited the osteogenic differentiation capacity of PDLSCs by affecting the expression of Smad1. Conclusion Our findings suggest that NaB inhibits the osteogenic differentiation of PDLSCs by activating FFAR2 and decreasing the expression of Smad1.
 
Article
Background Oral squamous cell carcinoma (OSCC) is the most common cancer affecting the oral and maxillofacial region. This study aimed to investigate the role of cancer stem cells (CSCs) in angiogenesis and hypoxic response in OSCC. Methods This retrospective observational study evaluated 56 cases of OSCC using dual immunohistochemistry. Octamer-binding transcription factor 3/4 (OCT3/4) marker was used to evaluate CSC activity. Glucose transporter 1 (GLUT1) marker was used to evaluate the hypoxic response and angiogenesis, while endoglin (CD105) was used to evaluate the late stage of angiogenesis and blood vessel formation. Results Co-expression of OCT3/4 and GLUT1 was noted in 11 of 12 patients with grade III OSCC. However, we did not observe co-expression of these markers in 13 of 22 patients with grade I OSCC. Although we observed a significant correlation between co-expression of GLUT1 and OCT3/4 and tumor grade, there was no significant correlation between co-expression of OCT3/4 and CD105 and different grades of OSCC. Conclusions CSCs could play important roles in the initial stages of hypoxic response and angiogenesis. Our result reported that in higher grades of OSCC, GLUT1 as a first response to hypoxic situations might be a result of CSCs. Further studies are required to discover other biomarkers, their roles, and associated pathways of CSCs in OSCC.
 
Flowchart outlining the protocol adopted in this systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)
Risk of bias assessment on study level (A) and across studies (B). 1: Assessed confounding factors are dental materials, MRI sequences, magnetic force
Suggested guideline for the various orthodontic appliances based on material and the region of the MRI
Article
Background Before the magnetic resonance imaging (MRI) examination fixed orthodontic devices, such as brackets and wires, cause challenges not only for the orthodontist but also for the radiologist. Essentially, the MRI-safe scan of the fixed orthodontic tools requires a proper guideline in clinical practice. Therefore, this systematic review aimed to examine all aspects of MRI-safe scan, including artifact, thermal, and debonding effects, to identify any existing gaps in knowledge in this regard and develop an evidence-based protocol. Methods The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in “PIO” format was: “Does MRI examination influence the temperature of the orthodontic devices, the size of artifacts, and the debonding force in patients who have fixed orthodontic bracket and/or wire?” The search process was carried out in PubMed, PubMed Central, Scopus, and Google Scholar databases. The search resulted in 1310 articles. After selection according to the eligibility criteria, 18 studies were analyzed by two reviewers. The risk of bias was determined using the Quality In Prognosis Studies tool. Results Out of the eligible 18 studies, 10 articles examined the heating effect, 6 were about the debonding effect, and 11 measured the size of artifact regarding brackets and wires. Considering the quality assessment, the overall levels of evidence were high and medium. The published studies showed that heating and debonding effects during MRI exposure were not hazardous for patients. As some wires revealed higher temperature changes, it is suggested to remove the wire or insert a spacer between the appliances and the oral mucosa. Based on the material, ceramic and plastic brackets caused no relevant artifact and were MRI-safe. Stainless steel brackets and wires resulted in susceptibility artifacts in the orofacial region and could cause distortion in the frontal lobe, orbits, and pituitary gland. The retainer wires showed no relevant artifact. Conclusions In conclusion, the thermal and debonding effects of the fixed orthodontic brackets and wires were irrelevant or resoluble; however, the size of the artifacts was clinically relevant and determined most significantly the feasibility of fixed brackets and wires in MRI examination.
 
Relationship of VAS with BDI-II and STAI-S. VAS scores were positively correlated with BDI-II and STAI-S in BMS patients with low IAc. VAS: Visual Analogue Scale, BDI-II: Beck Depression Inventory-Second Edition, STAI-S: State-Trait Anxiety Inventory-State, IAc: Interoceptive Accuracy
Article
Background Different perspectives are needed to understand the pathophysiology of burning mouth syndrome (BMS), including physiological and psychological standpoints. The significance of interoception in chronic pain has been suggested. However, few studies have investigated this relationship in BMS. Therefore, we examined the role of interoception in BMS. Methods This is a cross-sectional study. BMS patients (N = 64) participated in the study. We used interoceptive accuracy (IAc) based on the heartbeat counting task. Then, participants were divided into high and low IAc groups, and their scores on clinical assessment including pain and psychological evaluation were compared. Results The Visual Analogue Scale scores indicating pain in low IAc patients, but not high IAc patients, were positively correlated with the Beck Depression Inventory-Second Edition (BDI-II) and the State-Trait Anxiety Inventory-State (STAI-S) Scores. Conclusions Interoception might play a role in the pathophysiology of BMS.
 
Article
Background With the application of surface sealant agents, smooth surfaces can be achieved in a shorter time when compared with conventional polishing. However, studies on the performance of these agents against chewing forces are not many. The purpose of this study was to evaluate the surface roughness and Streptococcus mutans adhesion on surface sealent coupled interim prosthetic materials after chewing simulation. Methods One hundred and twelve specimens were fabricated from two poly(methyl methacrylate) (Tab 2000, Dentalon Plus) and two bis-acryl (Tempofit, Protemp 4) interim crown materials and divided into 4 groups (n = 7) according to applied surface treatment: conventional polishing (control) and 3 surface sealant (Palaseal, Optiglaze, Biscover) coupling methods. The surface roughness values (R a ) were measured with a profilometer before (Ra0) and after aging through dynamic loading in a multifunctional chewing simulator for 10,000 cycles at 50 N load combined with integral thermocycling (between 5 and 55 °C) (Ra1). Specimens were incubated with Streptococcus mutans suspension and the total number of adherent bacteria was calculated by multiplying the counted bacterial colonies with the dilution coefficient. Results Surface sealant agent application significantly decreased the surface roughness compared with conventionally polished specimens, except for Optiglaze or BisCover LV applied Protemp 4 and Palaseal or Biscover LV applied Tempofit. Surface roughness after dynamic loading showed a statistically significant increase in all groups, except for the control groups of Tab 2000 and Protemp 4. A positive correlation was found between surface roughness values of interim prosthodontic materials and the quantitiy of Streptococcus Mutans. Conclusions Even though surface sealant agent application significantly decreased the surface roughness compared with conventionally polished specimens, dynamic loading significantly increased the surface roughness of all surface sealant coupled materials. The R a values of all test groups were higher than the plaque accumulation threshold (0.20 µm). Streptococcus mutans adhered more on rougher surfaces.
 
Article
Background Following periodontal plastic surgery in the treatment of recession defects, previous studies have reported that patients rate the esthetic outcomes more favorable than dental professionals. The root coverage esthetic score has been developed and suggested to serve as a comprehensive assessment instrument as it addresses several esthetic outcomes following root coverage procedures. However, no study has yet reported on patient use of this instrument. In the present study clinical, esthetic and patient-reported outcomes following periodontal plastic surgery were assessed. The primary objective was to compare the esthetic/clinical outcome as judged by the patient and by one dentist by using the root coverage esthetic score. The secondary objective was to evaluate the correlation between patient-reported outcomes, root coverage esthetic score and clinical parameters following treatment of recession defects. Materials and methods Subjects that had undergone periodontal plastic surgery were invited to score the treatment outcome according to the root coverage esthetic score, which subsequently also was professionally scored by a dentist. Thereafter, the subjects answered a questionnaire on patient satisfaction. All types of surgical root coverage procedures in canine or incisor teeth were included. Results A total of 34 subjects were included, presenting 46 treated recessions. No statistically significant different score was found comparing the root coverage esthetic score by the patient and the professional. The majority of subjects was satisfied with the treatment outcome, and most would have undergone the treatment again. Conclusion The root coverage esthetic score assessment can be conducted by patients and was not statistically significant different to that of the professional. Patient satisfaction is not always dependent on complete root coverage or the other clinical parameters included in the root coverage esthetic score.
 
CONSORT flow diagram. From November 2019 to April 2021, 25 participants (41 teeth) matched the eligibility criteria, and 24 participants (40 teeth) who agreed to participate were enrolled in this study. At four weeks after intervention, 20 participants (33 teeth) were assessed and 4 participants (7 teeth) were lost to follow-up due to the following reasons: busy work schedule (three teeth), Covid-19 (three teeth) and fever (one tooth)
Pain level in response to air stimuli before treatment and 4 weeks after treatment. A significant reduction of the pain level in response to air stimuli was observed after treatment in both groups (*P < 0.05)
Article
Background Recently, a novel zinc-containing desensitizer, CAREDYNE Shield, was developed. This new type of desensitizer induces chemical occlusion of dentinal tubules for desensitization and releases zinc ion for root caries prevention. Despite these features, its clinical effectiveness in the improvement of cervical dentine hypersensitivity remains to be elucidated. Thus, we aimed to evaluate the effectiveness of CAREDYNE Shield in patients with CDH. Methods Forty CDH teeth which matched the eligibility criteria were randomly allocated to two groups in a 1:1 ratio: the CAREDYNE Shield group (intervention group) and the Nanoseal group (control group). The pain intensity in response to air stimuli, gingival condition, and oral hygiene status of CDH teeth were assessed before and at 4 weeks after treatment. The primary outcome was the reduction of pain intensity in response to air stimuli from baseline to 4 weeks after intervention. Results From November 2019 to April 2021, 24 participants with 40 teeth were enrolled in this study and 33 teeth in 20 participants were assessed at 4 weeks after treatment. A significant reduction of pain in response to air stimuli was observed in both groups; however, no significant difference was observed between the groups. Conclusions This study showed that CAREDYNE Shield is effective for CDH and its effectiveness is similar to Nanoseal. Trial registration UMIN Clinical Trials Registry (UMIN-CTR), UMIN000038072. Registered on 21st September 2019, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000043331
 
Masseter muscle cross-sec < onal area was measured from 5 mm above the mandibular foramen parallel to the Frankfurt plane using CT images
Cephalometric measurements. A Anteroposterior cephalometric measurements. 1;DFFM at Menton (mm), 2;U1-L1 deviation (mm). B Lateral cephalometric measurements. 3;overjet (mm), 4;overbite (mm), 5;SNA angle (°), 6;SNB angle (°), 7;ANB angle (°), 8;GZN angle (°), 9;SN-MP angle (°). Cephalometric landmarks: menton (Me), midpoint of the upper incisor edge (U1), midpoint of the lower incisor edge (L1), sella (S), nasion(N), point A (A), point B (B), gonion (Go), arCculare (Ar). FM: facial midline, DFFM: DeviaCon from the facial midline
Comparison of masseter muscle length, width and area between before and after preoperative orthodonthic treatment
Figure shows a greater reduction of with and area compared to length
RelaFons between changes of cross secFonal masseter muscle area and changes of overbite and SNA angle
Article
Background The purpose of the current study was to investigate factors related to morphological changes in the masseter muscle after preoperative orthodontic treatment in patients with skeletal class III dentofacial deformities for analysis of muscle changes and malocclusions. Methods Twenty female patients with dentofacial deformities were included in the study. Computed tomography was performed before and after preoperative orthodontic treatment, and the lengths, widths, and cross-sectional areas of the masseter muscles were measured. Changes in these parameters were evaluated, and factors related to changes in masseter muscle area after preoperative orthodontic treatment were analyzed. Results The lengths, widths, and areas of masseter muscles were significantly smaller after preoperative orthodontic treatment. Smaller masseter muscle area was significantly associated with changes in overbite and pretreatment values of SNA angle. Conclusions Atrophy of the masseter muscle during preoperative orthodontic treatment was greater in patients with increased open bite due to improved dental compensation in patients with skeletal class III dentofacial deformities with maxillary retraction.
 
The results of oral functions. a The results of LC. There was no significant difference about the mean LC between RE and NR at both BL and 12 M. b The results of TP. There was no significant difference about the mean TP between RE and NR at both BL and 12 M. c The results of OM. There was no significant difference about the mean OM between RE and NR at both BL and 12 M
The results of swallowing functions a: The results of MASA-C. There was no significant difference about the mean MASA-C score between RE and NR at both BL and 12 M. b: The results of FOIS. There was no significant difference about the mean FOIS score between RE and NR at both BL and 12 M
Article
Background Head and neck cancer (HNC) treatment can cause oral morbidities, such as oral dryness and dysphagia, affecting the patient’s quality of life (QOL). The relationship between oral functions and QOL in patients with early-stage HNC remains poorly studied. This study aimed to evaluate changes in the QOL of patients with early-stage HNC and identify factors that affect the QOL of these patients. Methods In this prospective cohort study, 37 patients who underwent early-stage (Stage I/Stage II) HNC treatment were evaluated for their oral function, swallowing function, and the QOL score at baseline (BL) and 12 months after surgical treatment (12 M). The participants were divided into two groups: patients who returned to the BL QOL score at 12 M (RE; n = 26) and those who did not (NR; n = 11). Results In total, 29.7% (11/37) patients with early-stage HNC did not return to the BL QOL score at 12 M. There was no significant difference between the RE and NR groups regarding the oral and swallowing function. Moreover, oral and swallowing function of all patients returned to the BL at 12 M. The NR group showed lower QOL scores than the RE group in the global health status, and “sticky saliva” parameters in the questionnaires. Conclusion Restoration of the oral function is insufficient to improve the QOL of patients with early-stage HNC. The treatment of these patients should instead consider several factors that affect their QOL.
 
PRISMA flow chart
Abtahi et al. [26, 27] studies dental implants bone marginal loss between groups
Bone level changes on dental implants affected by bisphosphonates
Trend lines regarding bone marginal loss on implants "associated" with bisphosphonates and non "associated" implants
Article
Objective Implantology represents the gold standard for oral rehabilitation, unfortunately, often, despite there are no local contraindications to this type of rehabilitation, there are uncertainties regarding the general health of our patients. Many patients nowadays take bisphosphonate drugs, often without first seeking advice from an oral surgeon or a dentist. The purpose of this review is precisely to highlight any contraindications to this type of treatment reported in the literature, in patients who take or have taken bisphosphonate drugs. Methods For this study the scientific information sources were consulted using as search terms “(“bisphosphonate AND “dental implant”)”, obtaining 312 results, these were subsequently skimmed according to the inclusion and exclusion criteria, and further evaluated their relevance to the study and the presence of requested outcomes. Results Only 9 manuscripts (RCTs, Multicentric studies and Clinical Trials) were included in this review, as they respected the parameters of this review, they were analyzed and it was possible to draw important results from them. Surely from this study it is understood that the use of bisphosphonate drugs does not represent an absolute contraindication to implant therapy, it is evident how adequate pharmacological prophylaxis, and an adequate protocol reduce the risks regarding implant failures. Furthermore, the values of marginal bone loss over time seem, even if not statistically significant, to be better in implant rehabilitation with bisphosphonate drugs association. Only a few molecules like risedronate, or corticosteroids, or some conditions like smoking or diabetes have shown a high risk of surgical failure. Conclusion Although this study considered different studies for a total of 378 patients and at least 1687 different dental implants, showing better results in some cases for dental implant therapy in cases of bisphosphonate intake, further clinical, randomized and multicentric studies are needed, with longer follow-ups, to fully clarify this situation which often negatively affects the quality of life of our patients and places clinicians in the face of doubts.
 
A 60 g orthodontic force is optimal to induce tooth movement. A, B The distance from the distal ridge of the first molar to the mesial ridge of the second molar is considered the tooth movement distance. The movement distance of the first molar increased in a force-dependent manner and reached a peak at 60 g (P < 0.01). When the orthodontic force was greater than 60 g, the tooth movement distance decreased. Red dotted lines indicate the tooth movement borders. All results are representative of three repeated experiments. *p < 0.05; **p < 0.01
A heavy orthodontic force induces external root resorption. A–D Images of HE staining show the effects of different orthodontic forces on dental pulp and periodontal tissues assessed by light microscopy. The orange-colored rectangles indicate areas shown at higher magnification in (A-i–D-i). No inflammation cells or multinucleated cells were observed in coronal pulp tissues of the control or experimental groups. The blue-colored rectangles indicate areas shown at higher magnificent in (A-ii–D-ii). Multi-nucleated osteoclasts (OCs) were observed in the heavy force group (100 g) at the mesial side of the distal root of the left maxillary first molar. M: mesial, D: distal. E–H Light microscope images of TRAP staining showing the effects of different orthodontic forces on the expression of TRAP-positive cells in dental pulp and periodontal tissues after orthodontic treatment. The results show that the number of OCs on the pressure side of the distal root of the left maxillary first molar increased following the increase of orthodontic forces. The orange-colored rectangles indicate areas shown at higher magnificent in (E-i–H-i). No OCs were observed in dental pulp tissues of the control or experimental groups. The blue-colored rectangles indicate areas shown at higher magnificent in (E-ii–H-ii). I The number of OCs increased significantly in the heavy force group (100 g) compared to the control group (P < 0.05). M: mesial, D: distal, T: tooth, AB: alveolar bone, arrowheads indicate OCs. All results are representative of three repeated experiments. *p < 0.05. The scale bars in (A–H) are 100 μm, and are 50 μm in (A-i–H-i), and in (A-ii–H-ii)
A heavy orthodontic force promotes the expression of RANKL in periodontal tissues, but does not affect OPG expression in dental pulp or periodontal tissues. A–D To further evaluate the expression of RANKL in dental pulp and periodontal tissues, we performed immunohistochemical staining. The results show that orthodontic forces promote the expression of RANKL on the compressive side of periodontal tissues. The orange-colored rectangles indicate areas shown at higher magnification in (A-i–D-i). E Semi-quantitative analysis of the percentage of RANKL-positive cells in pulp tissues, the RANKL expression was very low in pulp tissues, there was no significant difference among groups. The blue-colored rectangles indicate areas shown at higher magnification in (A-ii–D-ii). F Semi-quantitative analysis of the percentage of RANKL-positive cells in periodontal tissues on the pressure side of the first molar. The percentage of RANKL-positive cells on the compressive side of periodontal tissues in the experimental groups increased in a force-dependent manner (P < 0.01). G–J Immunohistochemical staining showing that there is no significant difference in the expression of OPG in dental pulp and periodontal tissues. The orange-colored rectangles indicate areas shown at higher magnification in (G-i–J-i). The blue-colored rectangles indicate areas shown at higher magnification in (G-ii–J-ii). K, L Semi-quantitative analysis of the percentage of OPG-positive cells in periodontal tissues on the pressure side of the first molar. The percentage of OPG-positive cells in dental pulp (K) and periodontal tissues (L) did not change significantly (P > 0.05). M: mesial, D: distal, T: tooth, AB: alveola bone. All results are representative of three repeated experiments. *p < 0.05; **p < 0.01. The scale bars in (A–J) are 100 μm, while those in (A-i–J-i, A-ii–J-ii) are 50 μm
A heavy orthodontic force promotes the formation of tertiary dentine. A–D Hard tissue milling slides show that the width of the tertiary dentine of the coronal pulp increased after orthodontic tooth movement. The yellow-colored rectangles indicate areas shown at higher magnification in (A-i–D-i), the white-colored rectangles indicate areas shown at higher magnification in (A-ii–D-ii). E Quantitative analysis showing that the width of tertiary dentine of the coronal pulp increases in a force-dependent manner, the heavy force group (100 g) exhibits a wider tertiary dentine compared with the control group (P < 0.05), F while no significant change was observed for the width of tertiary dentine of the root (P > 0.05). M: mesial, D: distal, P: pulp; D: dentine. All results are representative of three repeated experiments. *p < 0.05. The scale bars in (A–D) are 100 μm, while those in (A-i–D-i, A-ii–D-ii) are 50 μm
A mechanical compressive force upregulates RANKL expression by PDLSCs, which further promotes osteoclast differentiation of mononuclear cells. A–B RT-PCR results showing that mechanical compressive forces significantly up-regulate RANKL expression by PDLSCs and it was significantly higher than DPSCs (P < 0.05), while the OPG expression of PDLSCs and DPSCs showed no significant difference (P > 0.05). C–D TRAP staining shows that the cell culture medium of PDLSCs after compressive stimulation can promote the osteoclast differentiation of mononuclear cells. The TRAP positive cell number was significantly higher than in the positive control group and in the DPSC group (P < 0.05), and OCs in the PDLSC group created significantly more erosion areas on osteo assay surface plates (P < 0.05). All results are representative of three repeated experiments. *p < 0.05; **p < 0.01. The scale bars in (C) and (E) are 10 μm
Article
Background External root resorption is one of common complications of orthodontic treatment, while internal root resorption is rarely observed, and the difference between pulp and periodontal tissues during orthodontic treatment is still unknown. The purpose of this study was to evaluate the effects of orthodontic forces on histological and cellular changes of the dental pulp and periodontal tissues. Methods Orthodontic tooth movement model was established in Forty-eight adult male Wistar rats. The distance of orthodontic tooth movement was quantitatively analyzed. The histological changes of pulp and periodontal tissues were performed by hematoxylin–eosin staining, tartrate-resistant acid phosphate staining was used to analyze the changes of osteoclast number, immunohistochemistry analysis and reverse transcription polymerase chain reaction were used to examine the receptor of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) expression. The width of tertiary dentine was quantitatively analyzed. Tartrate-resistant acid phosphate staining and the erosion area of osteo assay surface plate was used to evaluate osteoclast activity. Results The orthodontic tooth movement distance increased in a force dependent manner, and reached the peak value when orthodontic force is 60 g. Heavy orthodontic force increased the RANKL expression of periodontal ligament srem cells (PDLSCs) which further activated osteoclasts and resulted in external root resorption, while the RANKL expression of dental pulp stem cells (DPSCs) was relatively low to activate osteoclasts and result in internal root resorption, and the dental pulp tend to form tertiary dentine under orthodontic force stimulation. Conclusions Heavy orthodontic forces activated osteoclasts and triggered external root resorption by upregulating RANKL expression in rat periodontal tissues, while there was no significant change of RANKL expression in dental pulp tissue under heavy orthodontic forces, which prevented osteoclast activation and internal root resorption.
 
Top-cited authors
Francesco G Mangano
  • I.M. Sechenov First Moscow State Medical University
Philip D Marsh
  • University of Leeds
Chun-Hung Chu
  • The University of Hong Kong
Edward C M Lo
  • The University of Hong Kong
Morenike Oluwatoyin Folayan
  • Obafemi Awolowo University