[Show abstract][Hide abstract]ABSTRACT: The aim of this study was to investigate a novel and convenient method of chemical treatment to modify the hydrophilicity of titanium surfaces. Sand-blasted and acid-etched (SLA) titanium surfaces and machined titanium surfaces were treated with sodium bicarbonate (NaHCO
) solution. The wetting behavior of both kinds of surfaces was measured by water contact angle (WCA) test. The surface microstructure was assessed with scanning electron microscopy (SEM) and three-dimensional (3D) optical microscopy. The elemental compositions of the surfaces were analyzed by X-ray photoelectron spectroscopy (XPS). The protein adsorption analysis was performed with fibronectin. Results showed that, after 1 M NaHCO
treatment, the hydrophilicity of both SLA and machined surfaces was enhanced. No significant microstructural change presented on titanium surfaces after NaHCO
treatment. The deprotonation and ion exchange activities might cause the enhanced hydrophilicity of titanium surfaces. The increased protein adsorption of NaHCO
-treated SLA surfaces might indicate their improved tissue-integration in clinical use.
Full-text Article · Nov 2015 · Journal of Nanomaterials
[Show abstract][Hide abstract]ABSTRACT: Statement of problem:
No study has evaluated consecutive changes in proximal contact tightness (PCT) between fixed implant prostheses and adjacent teeth after delivery.
The purpose of this clinical study was to investigate consecutive biological changes in PCT between fixed implant prostheses and adjacent teeth after placement.
Material and methods:
Eighteen participants who had been treated with a single first molar implant in the mandible were included. Mesial and distal PCT were measured using the custom-made contact pressure system at immediate crown delivery (T0), 3-month follow-up (T1), and 1-year follow-up (T2). The PCT of natural teeth in the mesial direction of the same quadrant was also measured at T2 as a control. Repeated-measures analysis of variance (ANOVA) and 1-way ANOVA were used for statistical analysis.
At T0, the PCT between fixed implant prostheses and adjacent teeth was designed deliberately to be higher than the PCT between natural teeth. Using multivariate analyses, the PCT between fixed implant prostheses and adjacent teeth decreased between T0 and T1 (P<.001), while there was no significant difference between T1 and T2 (P=.506). At T2, the distal PCT was tighter than the mesial PCT (P<.001); however, no statistical difference was found in the PCT between the implant-supported restoration and the natural teeth.
PCT decreased significantly at both mesial and distal sites over time. The major changes occurred over the 3-month period after crown delivery.
Article · Nov 2015 · The Journal of prosthetic dentistry
[Show abstract][Hide abstract]ABSTRACT: Achieving fast and long-term osseointegration is one of the major goals in dental implant design. Physic-chemical surface modification is a key to osseointegration improvement. Two types of alkaline modifications, 1 M sodium bicarbonate and 0.05 M sodium hydroxide, were applied on the sand-blasting and acid etching (SLA) titanium surface. After the alkaline treatments, superhydrophilic SLA surfaces were produced. The mRNA expression level of IL-1β of Raw264.7 cells cultured on the sodium bicarbonate treated SLA surface was inhibited compared with SLA and sodium hydroxide treated surfaces, while MMP-9 expression on the sodium hydroxide treated SLA surface was increased with comparison to SLA and sodium bicarbonate treated surfaces. Cell adhesion of osteoblast-like MG63 cells on surfaces with alkaline treatments were moderately more pronounced than that on the SLA surface. With comparison to SLA surface, the proliferation of MG63 cells was decreased, while the alkaline phosphatase (ALP) activity was enhanced on the sodium bicarbonate treated SLA surface after 3 days. An increased mRNA expression level of integrin αv of MG63 cells were observed on the alkali treated surfaces compared with the SLA surface. Integrin β1, osteocalcin (OCN) and bone morphogenetic protein-2 (BMP-2) were enhanced on the sodium bicarbonate treated SLA surface when compared to the SLA surface. The results imply that the inflammation-related gene expression of macrophage cells is changed on sodium hydroxide and sodium bicarbonate treated SLA surfaces; the early adhesion of osteoblast-like cells is enhanced by both alkaline treatments, while the osteogenic differentiation is improved on sodium bicarbonate treated surface. This journal is
[Show abstract][Hide abstract]ABSTRACT: Objective:
To evaluate the treatment outcome of the "All-on-4" immediate loading protocol via survival rate of the implants,survival rate of the prosthesis,marginal bone, postoperative complications and patient satisfaction.
In our study, 40 patients with 49 edentulous jaws (31 mandibles and 18 maxillae) were enrolled. Each jaw was restored by the shortened dental arch prosthesis supported by only 4 implants according to the All-on-4 protocol (All-on-4, Nobel Biocare AB, Goteborg, Sweden). For all the patients enrolled in the study, the loading was applied within 12 hours of surgery. The provisional prosthesis could be replaced by the final restorations within 6 to 12 months. In the present study, the survival rate of the both implants and restorations were calculated and analyzed. The radiographic evaluation of marginal bone level changes was measured. The values of the marginal bone level changes of the angled and axial implants were analyzed by the statistic software.
In the present study, totally 196 implants were inserted, of which 13 implants failed during the whole following up periods, with 11 implants of the maxillae and 2 of the mandibles. The survival rate of the prosthesis was 95.9% (47/49). The implant survival rate of the maxillae was 85.5% (65/76)while that for the mandibles was 98.3%(118/120). The implant survival rate of the angled implants was 91.8% (90/98), while that for the straight implants was 95.0% (93/98). No significant difference in marginal bone loss was found between angled and axial implants in the 12-month evaluation according to the Wilcoxon rank sum test (P>0.05). During the follow-up period,mechanical complications as fracture of the provisional prostheses, loose of the retain screw, or crack of the artificial teeth were found in 20 prostheses.
The present preliminary data of the short term observation suggest that the "All-on-4" immediate loading protocol is a viable treatment modality for the edentulous jaws. However, long term clinical random controlled trials with large samples are still needed to confirm the validity of the technique.
Article · Oct 2014 · Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences
[Show abstract][Hide abstract]ABSTRACT: Objective:
To evaluate the 10-year clinical results of implant prostheses in edentulous patients.
Between August 1994 and November 2009, 762 implants were placed in 127 patients (162 jaws) with the mean age of (56.0 ± 10.9) years in Peking University, School and Hospital of Stomatology. Sinus lift, guide bone regeneration (GBR) and onlay graft were used according to the indications of bone defect types. Overdentures and fixed bridges were delivered.Overdentures were retained/supported by ball, magnet, telescopic crown or milled bar. Clinical evaluation included peri-implant soft tissue health status, prostheses functional status and complications.Radiographic evaluations were conducted at operation day, 3 months post-operatively, right after prostheses delivery, and annually afterwards. Clinical data were collected and analyzed.
Of the 127 patients, 116 were edentulous mandible and 46 edentulous maxilla, with a mean follow-up period 109.2 months(45-228 months). Thirteen implants were lost and the 10-year implant cumulative survival rate was 97.8% and the prostheses success rate was 100.0%. The prevalence of peri-implantitis was 3.8% (29/762). Sixty-seven point nine percent of the patients underwent implant placement without bone graft.Sinus lift technique and guided bone regeneration technique were the most often used with 84.8% (39/46) in the upper jaws and 6.2% (10/162) in the total jaws respectively. Seventy-one percent of the cases(115/162) was overdentures. Telescopic, milled-bar, and magnetic retained/supported overdentures were the most commonly used with 34.8% (40/115) , 27.0% (31/115) , and 20.0% (23/115) respectively. The implant-supported fixed prostheses included adhesive retained fixed bridges and screw retained fixed bridges with the ratio of 19.1% and 80.9% respectively. The prevalence of 10-year post-prosthodontic complications was 53.5% (68 cases). The most common complications were prosthetic and uperstructure complications.
The 10-year implant-retained/supported prostheses was a successful modality in edentulous cases.Sinus lift technique and guided bone regeneration technique are the most commonly used techniques with predictable clinical results. Telescopic crowns milled bar and magnet with 4-6 implants retained/supported overdenture were the most often used retention systems and telescopic crown overdenture had more advantages in terms of long-term maintenance and satisfaction.
Article · Jun 2014 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract]ABSTRACT: To evaluate the applicability, accuracy and clinical outcome of the computer assisted design and computer assisted manufacture (CAD & CAM) tooth-supported implant surgical guide in the mandibular free-end partially edentulous patients with insufficient vertical bone height.
According to the inclusion criteria, 3 patients (2 women, and 1 man) with the mean age of 45 years (from 44 to 46 years) with 10 implant sites were involved in this study. With the help of Computer-assisted-design software to plan and simulate the surgical strategies, the implant surgical guides were fabricated via the rapid prototyping technique, then the guided implant placement was implemented, finally the post-surgical evaluations were accomplished by the clinical and radiographic examinations.
Ten implants were placed in 3 mandibles via the surgical guides, and the implant supported non-split restorations were in place. All the implant restorations revealed good clinical function until the last review. No inferior alveolar nerve injury was detected by the clinical neurosensory test. The immediate post surgical CBCT was performed to confirm a safe distance of 1.5 to 3.0 mm between the implant apical and the nerve canal. The deviations between the planed and the actually placed implant were: coronal deviation (0.84±0.30) mm (0.31-1.24 mm); apical deviation (1.42±0.52) mm (0.52-2.36 mm); angular deviation 7.65°±1.84° (4.43°-9.81°).
In case of distal free-end partially edentulous with insufficient vertical bone height in the posterior mandibular region, computer assisted surgical design and guided surgery can offer a treatment option with minimal invasiveness and a shorter treatment period, and avoid the complicated bone augmentation procedure and the high risk of nerve transposition. This technique is clinically and technically feasible, but the cases using this technique should be strictly selected according to the indication.
Article · Apr 2014 · Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences
[Show abstract][Hide abstract]ABSTRACT: Purpose:
To evaluate the outcome and special characteristics of immediate implant rehabilitation using the All-on-Four treatment concept in completely or potentially completely edentulous Chinese patients.
Materials and methods:
A convenience sample consisted of 69 consecutive patients (37 men, 32 women; mean age: 56.7 years) treated with immediate implant placement and full-arch prosthodontic provisional prostheses between April 2008 and December 2011. Of 344 implants (192 mandibular, 152 maxillary), 240 implants were placed in fresh extraction sites. The remaining 104 implants were placed in healed sites. Implants were immediately loaded with a fixed full-arch provisional prosthesis. Implant survival rate, marginal bone loss, abutment selection, complications, and subjective patient responses were recorded during follow-up.
Implant survival rate was 96.2% at 33.7 months of mean follow-up (range: 12 to 56 months). A statistically significantly higher implant survival rate was found in the mandible (99.0% vs 92.8%) (P < .05). No significant difference existed between survival rates for implants placed in postextraction sites and healed sites (P > .05). Peri-implant marginal bone loss around upright implants and tilted implants was 0.7 ± 0.2 mm and 0.8 ± 0.4 mm, respectively. All patients reported satisfactory treatment outcomes.
The modified All-on-Four treatment concept provides predictably favorable outcomes in completely or potentially completely edentulous patients and is well suited to the sociodemographic needs of Chinese patients. Exploratory use of a surgical guide was limited because of mouth opening, and more angulated abutments were needed in anterior upright implants of the maxilla.
Article · Nov 2013 · The International journal of prosthodontics
[Show abstract][Hide abstract]ABSTRACT: To measure passive tactile threshold of implant-supported single crowns (ISSC) in six orthogonal orientations, to analyze impact factors, and to guide the occlusal adjustment in a personalized manner.
The passive tactile thresholds of 24 implant-supported single crowns (5 maxillary anterior teeth, 7 maxillary posterior teeth and 12 mandibular posterior teeth) from 19 ISSC patients (8 men and 11 women, from 25 years old to 56 years old) were measured in six orthogonal orientations (four horizontal orientations of labial or buccal, lingual, mesial and distal, and two axial orientations of apical and coronal) using a digital test system for tactile function of teeth.SPSS 19.0 for windows was used to analyze impact factors, using double-sided test, with a significance level of 0.05. Paired-samples t test was used to test the difference between implant-supported single crowns and the controlled natural teeth, and between different time points. One-way ANOVA was used to test the difference between different orientations, maxilla-mandibular anterior-posterior, and men-women.
The passive tactile thresholds of ISSC and control teeth were (1282 ± 709) and (40 ± 40) mN respectively. The difference was of statistical significance (P < 0.001). The passive tactile thresholds of buccal-lingual, mesial-distal and axial of ISSC were (1334 ± 696), (1102 ± 605) and (1412 ± 791) mN respectively, of which, the difference between mesial-distal and axial was of statistical significance (P < 0.05). The passive tactile thresholds of ISSC of maxillary anterior teeth, posterior teeth and mandibular posterior teeth were (1003 ± 616), (1302 ± 620) and (1386 ± 769) mN respectively, of which, the difference between maxillary anterior teeth and posterior teeth was of statistical significance (P < 0.05). The passive tactile thresholds of ISSC of men and women were (1751 ± 784) and (946 ± 393) mN respectively, the difference was of statistical significance (P < 0.001). The passive tactile thresholds of ISSC of one-week and one-month after wearing the teeth were (1421 ± 826) and (1411 ± 814) mN respectively, the difference was of no statistical significance (P > 0.05).
The passive tactile threshold of ISSC was more than 65 times as much as that of the natural teeth. There was statistical significance between different orientations, between maxillary anterior and posterior teeth, and between men and women. No statistical significance was found between maxillary and madibular posterior teeth and between one-week and one-month after wearing the teeth.
Article · Aug 2013 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract]ABSTRACT: To investigate the normal occlusal force distribution and the characteristics of the occlusion time at different occlusion position using T-Scan III occlusal analysis system.
Fifty-three volunteers with normal occlusion, including 29 males and 24 females, were included in this study. The average age was (25.9 ± 2.1) years old. T-Scan III occlusal analysis system was used to measure the occlusal force distribution and the time character of normal occlusion at intercuspal position, protrusive position, and lateral excursive position.
At intercuspal position the left and right side molar teeth took the most part of force percentage, followed by (13.3 ± 4.3)%, (13.6 ± 5.4)%, (15.7 ± 7.1)%, (18.7 ± 7.5)% (6, 6, 7, 7); and 7654, 4567 took (61.3 ± 12.4)% force percentage; and the left and right sides took the respective percentages of (46.4 ± 7.0)%, (53.6 ± 7.0)%, the left side was significantly less than the right side(P < 0.05). At the protrusion position the region ( 21, 12) commitment to take the percentage of (85.1 ± 25.5)%. At left and right lateral position, 28% (13/46) and 30%(14/46) were cuspid-protected occlusion, and 33%(15/46) and 44%(20/46) were group fuctional occlusion, and 39%(18/46) and 26%(12/46) were multiple-protected occlusion. The average occlusion time was (0.34 ± 0.11) s, and disclusion time was (1.00 ± 0.39) s.
At intercuspal position the region from first premolar to second molar teeth were the occlusal force centers, and the second molar is the most;.the force concentrated in the area ( 21, 12) at the protrusion position. The lateral occlusal pattern is multiformity.
Article · Jun 2013 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract]ABSTRACT: To evaluate the outcomes of immediate post-extraction implant and immediate function according to All-on-4 immediate concept in edentulous patients.
The study included 46 patients with hopeless teeth. A total of 254 implants were immediately inserted after extraction and 56 fixed complete-arch all-acrylic prostheses finished and functioned on the day of extraction from June 2008 to March 2012 in Peking University School of Stomatology. At time of abutments connection, a panoramic radiograph was taken, and radiographic assessment of the marginal bone level was performed in every 6 months. Marginal bone level, integrity of the restoration, survival of the implants and degree of satisfaction of the patients were evaluated.
A total of 254 implants were immediate loading. Thirteen implants were lost 6 - 8 weeks after immediate loading and the survival rate of 94.9% (241/254). The marginal bone absorption was (0.7 ± 0.3) mm on average. All patients were satisfied with the clinical results.
Immediate post-extraction implant and immediate function technique can be a predictable technique. Further study is needed to determine the long-term results of the technology.
Article · Apr 2013 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology
[Show abstract][Hide abstract]ABSTRACT: Speech adaptation after oral rehabilitation is based on a complex interaction of articulatory and myofunctional factors. The knowledge of basic phonetic principles may help clinicians identify phonetic problems associated with prosthodontic treatment. The purpose of this article is to illustrate basic phonetic terminology, standard Chinese (Putonghua) phonetics, and the anatomic structures relevant for dentistry. In cooperation with a Chinese linguistic specialist, Chinese articulators were selected and are described and compared with English phonetics. Established test words and sentences aid the identification of mispronounced articulators and their related dental structures. The pronunciation of most consonants and vowels in standard Chinese is similar to English, but some of them, such as the retropalatals (/zh/[tʂ], /ch/[thʂ], /sh/[ʂ]), have notable differences. Palatal consonants (/j/[tɕ], /q/[tɕh], /x/[ɕ]) are unique to the Chinese phonetic system and are not found in English phonetics. The comprehension of the basic anatomic regions involved in Chinese phonetics may help prosthodontists treat patients whose native language is standard Chinese.
[Show abstract][Hide abstract]ABSTRACT: Esthetic considerations have become increasingly important in dental therapy. Evaluation of the soft tissue display during enjoyment smiling can provide useful information for esthetic oral rehabilitation. To date, no study has quantified the amount and frequency of soft tissue display in the area of the papilla. Photographic examination of 66 fully dentate patients with a mean age of 28.5 years was performed during enjoyment smiling. Digital processing and measurement of the tooth, gingival, and papillary display revealed that over 90% of subjects displayed papillae in the anterior teeth and first premolars during enjoyment smiling regardless of sex. The frequency of display in descending order consisted of maxillary lateral incisors (96%), central incisors (94%), canines (94%), first premolars (91%), second premolars (85%), and first molars (39%). The mean papillary display was 3.4 mm (range, 0.0 to 10.0 mm). There was no significant difference in the amount of papillary display between the sexes for anterior teeth, premolars, or first molars (P = .97, P = .79, and P = .48, respectively).
Article · Jan 2013 · The International journal of periodontics & restorative dentistry
[Show abstract][Hide abstract]ABSTRACT: The purpose of this study was to evaluate the influence of the placing depth of the implants with platform switching (Ankylos) on the marginal bone remodeling, by means of radiological observation.
111 Ankylos implants in the posterior mandible from 46 patients (20 male and 27 female) were enrolled in this study. Followed up by 58.1 months on average (from 36 to 85), 222 mesial and distal sites of these implants were evaluated by means of measuring the level of the marginal bone (LMB) on the panoramic radiograph.
Among these 111 successfully functional loaded implants, there were no significant differences with the marginal bone absorption values, no matter the implants were placed below, at, or above the bone level (P>0.05). Concerning the stabilization of the marginal bone, when placed below the bone level, 67.7% of the implant sites had their LMBs stabilized at or above the implant platform, and 23.3% absorbed vertically, respectively 19.7% and 80.3% when placed at the bone level, with significant difference (P<0.001).
Based on a long-term (over 3 years) observation, the implants placed below, as compared to at or above, the alveolar crest level, might have more chance to keep the marginal bone stabilized at or above the implant platform.
Article · Feb 2012 · Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences
[Show abstract][Hide abstract]ABSTRACT: To evaluate the influence of soft tissue aesthetic outcomes following application of adhensive fixed partial denture and implant supported temporary restoration in maxillary single tooth implant procedure. Discuss the feasibility and details of the shaping the soft tissue by combine adhensive fixed partial denture and implant-supported temporary restoration.
The study included 29 patients(Male: 17, Female: 12) with hopeless maxillary single tooth from Sept. 2008 to Dec. 2010. All patients received tooth extraction and implant treatment in department of oral implantology, Peking University School and hospital of Stomatology. The adhesive fixed partial denture as a provisional restoration was used to support the soft tissue of the tooth extraction socket after tooth extraction. The average time of patient wearing adhensive fixed partial denture was 3.7 months. The implant supported temporary restoration was delivered to shape the soft tissue after implant placement. The average time of implant supported provisional restoration using was 8.3 months. Soft tissue esthetic condition was evaluated through 4 main index reference pink esthetic score (PES) before tooth extraction and at the time of the final restoration. Clinical observe items also included the survival rate of fixed partial denture and rate of re-adhesive, integrity of temporary restoration and degree of satisfaction of the patients. The control group included 29 cases with removable denture or without temporary restoration. The base line differences between control group and experiment group were not statistically significant.
The survival rate of both the adhensive partial denture and implant-supported provisional restoration was 100%. The re-adhesive rate of adhesive partial denture was 16.2% during follow-up period. The PES at the time of final restoration were significant different between two groups by t test (7.48±0.51 vs. 5.69±0.71, P<0.000 1). Patients were satisfied with the clinical results.
This study indicates that fixed partial restoration and implant-supported provisional restoration could be used to support and to shape the soft tissue contour and to improve the aesthetic effects.
Article · Feb 2012 · Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences
[Show abstract][Hide abstract]ABSTRACT: Due to global migration, clinicians often see patients with different ethnic backgrounds. Planning esthetic prosthodontic treatment for patients with different ethnicities can be a challenge. The aim of this study is to analyze the smile features of Chinese individuals.
Sixty-two Han-Chinese subjects with a mean age of 28.5 years were enrolled and photographed. Standardized digital photographs were made to measure the height of displayed maxillary gingivae, papillae, and teeth during an enjoyment smile. The data were then compared with the data acquired from Caucasians in a previous study. Statistical analysis was performed using the Mann-Whitney test and two-factorial nonparametric analysis.
The mean display of the central incisors was 10 mm, with no significant difference between sexes (P = .74). The mean amount of display of the molars and premolars was significantly lower in Chinese (P < .001) than in Caucasians. The mean displayed gingiva in all subjects (n = 62) was 1.3 mm (0 to 8 mm). There was no significant difference between sexes (P > .05), but there was a significantly lower display of gingiva at the molars in Chinese (P < .001). Of all the subjects, 16.1% (n = 10) displayed gingivae from the central incisor to the first molar with a mean gingival height of 2.8 mm. The subjects showed a mean papilla height of 3.4 mm (0 to 11.6 mm) with no significant difference between sexes (P > .05). Again, a significantly lower display of papilla at the molar (P < .001) was found in Chinese. Of all subjects, 43.5% (n = 27) of all subjects showed papilla from the central incisor to the first molar. The mean papilla height of these subjects was 3.9 mm. All subjects displayed at least one papilla.
The results indicate that pink esthetics is a prime factor for both Chinese men and women in the esthetic restoration from the central incisors to the premolars.
Article · Feb 2012 · Quintessence international (Berlin, Germany: 1985)
[Show abstract][Hide abstract]ABSTRACT: To analyze smile features in maximum lip-dynamic in Chinese.
Sixty-two Han-Chinese, travelling in Germany, with a mean age of 28.5 years were enrolled and photographed. Standardized digital photos were made to measure the height of displayed maxillary gingiva, papilla and tooth during an enjoyment smile. Statistical analysis was performed using Mann-Whitney-U Test and non-parametric analysis.
The mean height of tooth display for the central incisors was 10 mm, with no significant difference between the gender (P > 0.05). The mean height of gingival display was 1.3 mm and the mean papilla height was 3.4 mm. There was no significant difference between the genders (P > 0.05). 31% (19/62) of the subjects belonged to high smile line type, 50% (31/62) to medium smile line type and 19% (12/62) to low smile line type.
The red esthetics is a paramount factor for Chinese men and women in the esthetic restoration. 81% of the Chinese studied showed various degree of gingival exposure from central incisor to the premolars, which defined the esthetic area for Chinese people. Papilla is a critical parameter for esthetic evaluation and treatment design. The ratio of high smile line in Chinese may be higher than that in Caucasian.
Article · Nov 2011 · Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology