[Show abstract][Hide abstract] ABSTRACT: Early transition from breastfeeding and non-nutritive sucking habits may be related to occlusofacial abnormalities as environmental factors. Previous studies have not taken into account the potential for interactions between feeding practice, non-nutritive sucking habits and occlusal traits. This study assessed the effects of breast-feeding duration, bottle-feeding duration and non-nutritive sucking habits on the occlusal characteristics of primary dentition in 3-6-year-old children in Peking city.
This cross sectional study was conducted via an examination of the occlusal characteristics of 734 children combined with a questionnaire completed by their parents/guardians. The examination was performed by a single, previously calibrated examiner and the following variables were evaluated: presence or absence of deep overbite, open bite, anterior crossbite, posterior crossbite, deep overjet, terminal plane relationship of the second primary molar, primary canine relationship, crowding and spacing. Univariate analysis and multiple logistic regressions were applied to analyze the associations.
It was found that a short duration of breast-feeding (never or ≤6 months) was directly associated with posterior cross bite (OR = 3.13; 95%CI = 1.11-8.82; P = 0.031) and no maxillary space (OR = 1.63; 95%CI = 1.23-2.98; P = 0.038). In children breast-fed for ≤6 months, the probability of developing pacifier-sucking habits was 4 times that for those breast-fed for >6 months (OR = 4.21; 95%CI = 1.85-9.60; P = 0.0002). Children who were bottle-fed for over 18 months had a 1.45-fold higher risk of nonmesial step occlusion and a 1.43-fold higher risk of a class II canine relationship compared with those who were bottle-fed for up to 18 months. Non-nutritive sucking habits were also found to affect occlusion: A prolonged digit-sucking habit increased the probability of an anterior open bite, while a pacifier-sucking habit associated with excessive overjet and absence of lower arch developmental space.
Breastfeeding duration was shown to be associated with the prevalence of posterior crossbite, no maxillary space in the deciduous dentition and development of a pacifier-sucking habit. Children who had a digit-sucking habit were more likely to develop an open bite.
[Show abstract][Hide abstract] ABSTRACT: Background
Although caries and malocclusion occur with a high prevalence in Chinese school-age children, there were no appropriate instrument to assess the oral health-related quality of life (OHRQoL) for this population. The aim of our study was to develop a Chinese (Mandarin) version of the Child Oral Health Impact Profile-Short Form 19 (COHIP-SF 19) and provide a preliminary test of its psychometric properties.Methods
The Chinese version of COHIP-SF 19 was developed through a standard translation and back translation procedure. The psychometric properties of the instrument were tested among 644 school-age children in Beijing, China, including the internal consistency, test-retest reliability, discriminant and convergent validity. A Mann-Whitney U test was used to determine the capability of the instrument to differentiate children with different caries and malocclusion outcomes. And partial Spearman correlations were used to determine the relationships between the OHRQoL scores and clinical-severity indicators and self-perceived health ratings, respectively.ResultsChinese school-age children had relatively high OHRQoL scores, in spite of the fact that oral impacts were quite common (56.3%). The internal consistency and retest reliability were good to excellent with a Chronbach¿s alpha of 0.81 and an intra-class correlation coefficient (ICC) of 0.77. Children who had active tooth decay or severe malocclusion had significantly lower COHIP-SF 19 scores (P ¿0.001). Girls had somewhat higher scores in the oral health and functional well-being subscales (P <0.05), while children from rural districts had lower scores than children from urban areas (P <0.05). We observed a low to moderate correlation between the overall COHIP-SF 19, subscale scores and clinical severity indicators as well as self-perceived health ratings, after adjustment for children¿s age, gender, and school district (¿r s ¿ =0.11 - 0.51, P <0.05).Conclusion
We confirmed satisfactory psychometric properties for the Chinese version of COHIP-SF 19 in a community sample of Chinese school-age children. The OHRQoL instrument should play a more important role in future clinical studies, epidemiological surveys and potential public health policy in China.
Preview · Article · Nov 2014 · Health and Quality of Life Outcomes
[Show abstract][Hide abstract] ABSTRACT: To compare the children's oral health habits and oral-health-related quality of life following treatment under dental general anesthesia (DGA) and passive restraint (PR).
In the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, twenty eight 2 to 4-year-old patients treated under DGA and thirty five treated under PR were collected in this non-randomized controlled trial. The general information including age and decayed, missed and filled teeth(dmft), dental plaque index was recorded preoperatively. Two questionnaires, questionnaire of oral health habits and early childhood oral health impact scale (ECOHIS) were completed by parents before and 6 months after treatment (including restoration, root canal treatment, stainless steel crown, tooth extraction, etc.). Six months after treatment, dental plaque index and restoration were reexamined.
The patients were significantly elder in DGA group [(3.1±0.6) years old, P < 0.05], and the mean dmft was significantly higher (13.1±4.1, P < 0.001) in DGA group. The postoperative dietary habits and brushing habits significantly improved in PR group, but not in the DGA group. However, according to the results of ECOHIS, the occurrence of pain, the impacts of patients on daily life, psychology and family due to the oral diseases significantly decreased in DGA group (P < 0.05), while in PR group, only the occurrence of pain reduced (P < 0.05). No statistical difference was found between the two groups in new caries or recurrent caries (PR group: 37.1%, DGA group: 39.3%), secondary caries (PR group: 4.1%, DGA group: 2.3%), and failure of the restoration (PR group:1.5%, DGA group: 2.7%).
Each behavior management technique has advantages and drawbacks, and no statistical differences were found in the treatment results between the two techniques.
No preview · Article · Sep 2014 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract] ABSTRACT: Objective: To investigate the expression pattern of E- and P-cadherin in murine tooth germs at different stages.
Methods: Mandible samples of CD1 mice from embryonic day 12.5 to postnatal day 3.5 were collected. The expression of E- and P-cadherin in murine mandibular first molar germs was detected by immunofluorescence and observed under confocal fluorescence microscope. H&E staining was performed for tissue morphology.
Results: Both E- and P-cadherin were expressed in the enamel organ through early developmental stages. E-cadherin expression was increased in polarizing pre-ameloblasts, whereas P-cadherin expression declined. P-cadherin was also expressed in mature ameloblasts.
Conclusion: E- and P-cadherin expressed in different spatiotemporal expression patterns, indicating their individual functions during tooth development. P-cadherin might function in the secretion and mineralization of enamel.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To determine the effect of mechanical tooth cleaning by toothbrush and dental floss on mutans streptococci in the saliva of preschool children.
Materials and methods:
This blinded, randomised controlled clinical trial included 54 3-year-old preschool children with detectable mutans streptococci in saliva. The children were randomly divided into a test and a control group. Dental college students cleaned the teeth of test group participants with toothbrush and dental floss under the indication of a plaque disclosing agent once a day. The control group received no intervention. Dentocult SM Strip mutans (D-SM) strips were used to test the mutans streptococci in saliva.
The D-SM test scores declined from 1.82 to 0.95 for the test group after the teeth were cleaned 10 times (P < 0.001) and the scores increased to 1.62 after tooth cleaning ceased for 2 weeks (P > 0.05 compared with baseline). The D-SM level of the control group did not change significantly.
Meticulous and continuous plaque control with toothbrush and dental floss can decrease the mutans streptococci level in preschool children. However, the effect ceased as the intervention ceased.
No preview · Article · Jun 2014 · Oral health & preventive dentistry
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of modified Nance arch appliance in the treatment of ectopic eruption of maxillary first permanent molar.
Thirty children with unilateral ectopic eruption of maxillary first permanent molar were treated with modified Nance arch appliance. The mesial angle of the maxillary first permanent molars and the magnitude of the primary second molar distal root lesion before and after treatment were measured on the panoramic radiographs and analyzed statistically.
All 30 children completed the treatment. The mesial angle of the ectopic side significantly changed from (75.2 ± 7.6) ° before the treatment to (92.9 ± 5.2) ° after the treatment (t = -11.082, P < 0.05). The root lesion of the ectopic side significantly enlarged after the treatment, but there was no significant change on the normal side.
The treatment of ectopic eruption of the maxillary first permanent molar using modified Nance arch appliance was successful. The attention should be paid to the magnitude of the primary second molar distal root lesion before and after treatment and it is suggested to start the treatment when mild root resorption appears.
No preview · Article · Apr 2014 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract] ABSTRACT: Recent studies have reported that supernumerary teeth were observed in the maxillary incisor area in several Pax6 homozygous mutant mouse and rat strains. To date, it remains unknown whether Pax6 is expressed during tooth development in any species. The study aimed to analyze the expression of Pax6 during mouse incisor and molar development. C57BL/6J mouse embryos on days E12.5, E13.5, E14.5, E16.5 and E18.5 were produced. Heads from these embryos, as well as from P1.5 mice, were processed for paraffin wax embedding (N ≥ 3 for each stage) and prepared for immunohistochemistry. Pax6 immunostaining was found in all tooth germs examined. At the E12.5 dental placode, E13.5 bud stage, E14.5 cap stage and E16.5 early bell stage, Pax6 was expressed in ectodermally derived tissues of tooth germs and oral epithelia adjacent to the tooth germs. Cells in the underlying dental ectomesenchyme that showed Pax9 expression were Pax6 negative. At E18.5 and P1.5, Pax6 was expressed in more differentiated ameloblasts and cells of the stratum intermedium and stellate reticulum that were derived from the oral epithelium, as well as in mesenchyme-derived differentiated odontoblasts. Pax6 expression was also observed in the submandibular gland, tongue filiform papilla and hair follicle at E16.5 and P1.5. The present study demonstrated that Pax6 was expressed in incisor and molar germs during mouse tooth development. The results provide a basis for exploring the function of Pax6 during tooth development.
No preview · Article · Jan 2014 · Journal of molecular histology
[Show abstract][Hide abstract] ABSTRACT: Objectives: The purpose of this study was to evaluate the effect of alendronate (Aln) on the proliferation and differentiation of the human periodontal ligament stem cells (hPDLSCs) in vitro.
Methods: hPDLSCs were isolated and cultured in vitro. After treated with Aln in growth medium for 24, 48, 72 h, cell proliferation of hPDLSCs was assessed by Cell Counting Kit-8. hPDLSCs were treated with Aln in osteogenic induction medium for 14 days, and osteogenic differentiation was evaluated by alizatin red staining, ALP activity, and the expression of osteogenic related genes. Similarly, the adipogenic differentiation of Aln treated hPDLSCs was assessed by oil red O staining and the expression of adipogenic related genes.
Results: Aln (ranging from 0.01nM to 1μM) enhanced cell proliferation of hPDLSCs, reaching peak level at 0.01μM. In addition, Aln increased the expression level of osteogenic related genes, as well as alkaline phosphatase activity and calcium accumulation after osteogenic induction in a dose-dependent way. In contrast, Aln decreased the expression of adipogenic related genes, and total droplet numbers indicated by Oil Red O staining after adipogenic induction.
Conclusions: Aln promoted the proliferation and osteogenic differentiation of hPDLSCs, while inhibited adipogenic differentiation of hPDLSCs suggesting its potential of improving periodontal tissure regeneration.
[Show abstract][Hide abstract] ABSTRACT: The health of human teeth depends on the integrity of the hard tissue and the activity of the pulp and periodontal tissues, which are responsible for nutritional supply. Without the nourishing of the pulp tissue, the possibility of tooth fracture can increase. In immature permanent teeth, root development may be influenced as well. This study explored the potential of using autologous dental pulp stem cells (DPSCs) to achieve pulp regeneration in a canine pulpless model.
The establishment of the pulpless animal model involved pulp extirpation and root canal preparation of young permanent incisor teeth in beagles. Autologous DPSCs were obtained from extracted first molars and expanded ex vivo to obtain a larger number of cells. The biological characteristics of canine DPSCs (cDPSCs) were analyzed both in vitro and in vivo by using the same method as used in human DPSCs. cDPSCs were transplanted into the pulpless root canal with Gelfoam as the scaffold, and root development was evaluated by radiographic and histologic analyses.
cDPSCs with rapid proliferation, multiple differentiation capacity, and development potential were successfully isolated and identified both in vitro and in vivo. After they were transplanted into the pulpless root canal with Gelfoam as the scaffold, DPSCs were capable of generating pulp-like tissues containing blood vessels and dentin-like tissue. Thickening of the root canal wall was also observed.
This study demonstrates the feasibility of using stem cell-mediated tissue engineering to realize pulp regeneration in immature teeth.
No preview · Article · Feb 2013 · Journal of endodontics
[Show abstract][Hide abstract] ABSTRACT: Dens invaginatus is a rare developmental malformation of a tooth caused by the invagination of the tooth crown before biological mineralization occurs. The complex anatomy of these teeth makes nonsurgical endodontic treatment difficult and more so when there is presence of periapical periodontitis with open apex. The endodontic treatment of dens invaginatus is a challenge, especially in the case of periapical periodontitis with open apex. Pulp revascularization is a conservative endodontic treatment that has been introduced in recent years. Presented here is a variant approach for the treatment of immature dens invaginatus type II with periapical periodontitis, which combines filling of the invagination and pulp revascularization.
After accessing the pulp chamber, the main canal and the invagination were explored. The root was thoroughly disinfected by irrigating and medication, invagination was filled, and the main canal was revascularized. Then the coronal sealing was made by glass ionomer cement and composite resin. Radiograph taken regularly and computed tomography scan were used to investigate the healing of the periapical lesion and development of the root.
In the subsequent follow-up, the periapical lesion was completely eliminated, the open apex was closed, and the wall of the root was thickened.
For type II immature dens invaginatus with large periapical lesion, conservative endodontic treatment should be considered before periapical surgery. With sufficient infection control, pulp revascularization can be an effective alternative method.
Full-text · Article · Feb 2013 · Journal of endodontics
[Show abstract][Hide abstract] ABSTRACT: Cyclin D1 (CCND1) plays a critical role in the G1 to S-phase cell cycle transition. Data on the association between the CCND1 A870G polymorphism and oral cancer are conflicting. To assess the relationship between the CCND1 A870G genotype and the risk of developing oral cancer, we performed a meta-analysis. We searched PubMed to December 1, 2011, for studies on this topic that had been published in the English. For each study, we calculated odds ratios (ORs) and 95 % confidence intervals (CIs), assuming the frequency of allele comparison, homozygote comparison, recessive and dominant genetic models. We then calculated pooled ORs and 95 % CIs. Seven studies were included in the meta-analysis. The CCND1 G allele was not associated with oral cancer in the frequency of allele comparison (G vs. A: OR = 0.882; 95 % CI = 0.684-1.137; p = 0.001 for heterogeneity). In the subgroup analysis, the CCND1 G allele was associated with a borderline significantly decreased risk of developing oral cancer in Asians in the frequency of allele comparison (G vs. A: OR = 0.800; 95 % CI = 0.636-1.006; p = 0.089 for heterogeneity), and the association between the GG genotype and oral cancer was significant in Asians with respect to both the homozygote comparison (GG vs. AA: OR = 0.644; 95 % CI = 0.491-0.843; p = 0.186 for heterogeneity) and the dominant genetic model (GG + AG vs. AA: OR = 0.713; 95 % CI = 0.584-0.870; p = 0.293 for heterogeneity). Our analysis provides evidence that genotypes for the CCND1 A870G polymorphism may be associated with an increased risk of developing oral cancer in the Asian population.
No preview · Article · Oct 2012 · Molecular Biology Reports
[Show abstract][Hide abstract] ABSTRACT: The most important events during the regulation of tooth development were inductive interactions between the epithelial and
mesenchymal tissues. The expression of Pax9 had been shown to specifically mark the mesenchymal regions at the prospective sites of all teeth prior to any morphological
manifestations. Here, we investigated the PAX9 gene as a candidate gene for hypodontia in five unrelated Chinese patients with tooth agenesis. Direct sequencing and restriction
enzyme analysis revealed a novel heterozygous mutation c.480C>G (p.160Tyr>X, Y160X) in a patient who was missing 20 permanent
teeth (the third molars excluded) and 6 primary teeth. The mutation was a nonsense mutation, leading to a premature stop codon
in exon 2 of PAX9 gene. PCR analysis of complementary DNA from cultured lymphocytes of the affected individual could not indicate the complete
degradation of the mutated transcript. Promoter reporter assays revealed reduced transcriptional activity of the mutated PAX9
protein suggesting that the severe phenotype may result from haploinsufficiency of PAX9. In another patient with 15 missing
permanent teeth (the third molars excluded), we found the c.219insG mutation previously reported by Stockton.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the efficacy of laser fluorescence (LF) device in detecting approximal caries in primary molars.
Two hundred and sixteen primary molars from 96 children were inspected visually to identify possible caries with contact approximal surfaces. Target molars and their contralateral molars were examined using bitewing radiographs (BR) and LF. Depending on the examination findings, invasive treatments were performed on molars to identify the presence of cavitation.
Of 256 surfaces evaluated from 216 primary molars, 128 were intact, 39 had white spots, and 89 had cavities. At the white-spot threshold, sensitivity and specificity, respectively, were 2.56% and 94.87% for visual inspection (VI); 64.10% and 97.43% for BR; and 56.41% and 94.87% for LF. At the cavity threshold, sensitivity and specificity, respectively, were 70.79% and 95.51% for VI; 97.75% and 93.26% for BR; and 92.14% and 97.75% for LF. Significant differences between intact surfaces and white spots, and white spots and cavities were shown through LF readings.
Both LF and BR can detect cavitations on approximal surfaces of primary molars. LF could be an alternative to radiographs in detecting approximal caries in primary molars.
No preview · Article · Sep 2011 · International Journal of Paediatric Dentistry
[Show abstract][Hide abstract] ABSTRACT: International Journal of Paediatric Dentistry 2011; 21: 422–431
Background. The genotypic diversity of both Streptococcus mutans and Streptococcus sobrinus in children with different caries experience remains unclear.
Aim. To investigate the genotypic diversity of S. mutans and S. sobrinus in children with severe early childhood caries (SECC) and in caries-free (CF) children.
Methods. Stimulated saliva of 87 SECC and 91 CF children aged 3–4 years was collected and submitted to cultivation, and MS colonies were enumerated. The genomic fingerprint analysis of S. mutans and S. sobrinus was carried out using AP-PCR.
Results. One to five genotypes of S. mutans were colonized in an oral cavity of SECC and CF children; 85.5% SECC children and 57.9% CF children harboured more than one genotype of S. mutans. One to three genotypes of S. sobrinus were detected from each SECC child; 31.25% SECC children harboured more than one genotype of S. sobrinus. And one genotype was colonized in each CF child. S. mutans isolates from different individuals displayed distinctive DNA fingerprints.
Conclusions. DNA fingerprints of S. mutans and S. sobrinus isolates from 3- to 4-year-old children displayed genetic polymorphism, and S. mutans has greater genetic diversity than S. sobrinus. SECC children harboured more genotypes of S. mutans and S. sobrinus than CF children.
Full-text · Article · Jun 2011 · International Journal of Paediatric Dentistry
[Show abstract][Hide abstract] ABSTRACT: Cleidocranial dysplasia (CCD) is a dominantly inherited skeletal dysplasia caused by mutations in the osteoblast-specific transcription factor-encoding gene, RUNX2. To correlate different RUNX2 mutations with CCD clinical spectrum, we studied six independent Chinese CCD patients. In five patients, mutations were detected in the coding region of the RUNX2 gene, including two frameshift mutations and three missense mutations. Of these mutations, four were novel and one had previously been reported. All the detected mutations were exclusively clustered within the Runt domain that affected conserved residues in the Runt domain. In vitro green fluorescent protein fusion studies showed that the three mutations--R225L, 214fs and 172fs--interfered with nuclear accumulation of RUNX2 protein, while T200I mutation had no effect on the subcellular distribution of RUNX2. There was no marked phenotypic difference between patients in craniofacial and clavicles features, while the expressivity of supernumerary teeth in our patient cohort had a striking variation, even among family members. The occurrence of intrafamilial clinical variability raises the view that hypomorphic effects and genetic modifiers may alter the clinical expressivity of these mutations. Our results provide new genetic evidence that mutations involved in RUNX2 contribute to CCD.
[Show abstract][Hide abstract] ABSTRACT: Objective: To evaluate the clinical effects of a total-etching adhesive system (Adper Single Bond 2, SB) and a self-etching adhesive system (Adper Prompt, PT) in restorations of pits and fissures caries in children.
Methods: The study was approved by the Human Research Ethics Committee of Peking University (No. IRB00001052-06054). Parental consent for the child's participation was obtained. A total of 142 carious molars from 52 children, were divided randomly into two groups, using PT or SB respectively. The modified United States Public Health Service (USPHS) evaluation criteria were used to evaluate the clinical effects at 6, 12, 18 and 24 months recall after treatment.
Results: After 24 months, the recall rate (of the teeth) is 85.9% and the survival rate is 100%. There were no statistic differences between the two groups at retention, marginal sealing, marginal staining, secondary caries and postoperative sensitivity. All of them were considered well during 24 months.
Conclusions: This study indicated that both SB and PT performed well when used in restorations of pits and fissures caries in children. Long-term performance need be evaluated further.