Accuracy assessment of a novel semiautomatic method evaluating bone grafts around the dental implant: an in vitro and ex vivo study.

The present study aimed to evaluate the accuracy and repeatability of morphological contour interpolation (MCI)-based semiautomatic segmentation method for volumetric measurements of bone grafts around dental implants. Three in vitro (one with a cylinder and two with a geometrically complex form) and four ex vivo models (peri-implant cylinder-shaped bone defect) were created for imitating implant placement with simultaneous guided bone regeneration (GBR) procedure. Cone beam computerized tomography (CBCT) scans of all models were obtained with the same parameters. For volumetric measurements, the actual volumes of bone grafts in models were assessed by computer-aided calculation and both manual and MCI-based methods were utilized as test methods. The accuracy of the methods was evaluated by comparing the measured value and the actual volume. The repeatability was assessed by calculating the coefficients of variation of repeated measurements. For the accuracy of three dimensional (3D) reconstructions, the computer-designed corresponding models were set as the reference and the morphological deviation of 3D surface renderings created by two methods were evaluated by comparing with reference. Besides, measurement time was recorded and a comparison between the two methods was performed. High accuracy of the MCI-based segmentation method was found with a discrepancy between the measured value and actual value never exceeding - 7.5%. The excellent repeatability was shown with coefficients of variation never exceeding 1.2%. The MCI-based method showed less measurement time than the manual method and its 3D surface rendering showed a lower deviation from the reference.

Peri-implant conditions and marginal bone loss around cemented and screw-retained single implant crowns in posterior regions: A retrospective cohort study with up to 4 years follow-up.

The aim of the present study was to identify the peri-implant conditions (bleeding on probing (BOP), pocket probing depth (PPD), modified plaque index (mPI)) and marginal bone loss (MBL, marginal bone level change between follow-up and occlusal loading) around cemented and screw-retained posterior single crowns on tissue-level implants. The study was a retrospective cohort study with up to 4 years (mean 2.5 years) follow-up. Patients with either cemented or screw-retained crowns in posterior regions were included. Implant survival, technical complications, BOP, PPD, mPI, MBL, biologic complications (peri-implant mocositis and peri-implantitis) were evaluated. Mann-Whitney U test was used to test the difference between the screw-retained group (SG) and cemented group (CG). 176 patients (SG: 94, CG: 82) were included. The implant survival rates were 100% in SG and 98.8% in CG. Prosthetic screw loosening was found in 8 restorations (8.7%) at follow-up visit. Peri-implant mucositis rate was significantly higher in the SG group (42.1%) than that in the CG group (32.2%) (P = 0.04). Six patients (6.38%) in the screw-retained group and 5 patients (6.10%) in the cemented group were diagnosed with peri-implantitis, the difference did not reach statistical significance (P>0.05). No significant difference of PPD, mPI and MBL were found between two groups (P = 0.11, 0.13 and 0.08, respectively). High implant survival rates were achieved in both groups. Cemented single crowns on tissue-level implants showed comparable peri-implant conditions in comparison with two-piece screw-retained crowns. Well-designed prospective cohort or randomized controlled clinical trials with longer follow-up are needed to confirm the result.

Long-term outcomes of narrow diameter implants in posterior jaws: A retrospective study with at least 8-year follow-up.

OBJECTIVE: The aim of this study was to evaluate the long-term survival, complications, peri-implant conditions, marginal bone loss, and patient satisfaction of fixed dental prostheses supported by narrow diameter implants (NDIs) in the posterior jaws. MATERIALS AND METHODS: This study was designed as a retrospective cohort study with a mean follow-up time of 10.1 years (SD: 2.5 years). Patients receiving NDIs in posterior jaw were reviewed. Implant survival, hardware complication, modified plaque index (mPI), peri-implant probing depth (PPD), percentage of bleeding on probing (BOP%), marginal bone loss (MBL), and patient satisfaction were evaluated. Log-rank test and t test were used to detect the influence of implant location and restoration type. RESULTS: Sixty-seven patients with 98 NDIs (Premolar site: 81, Molar site: 17, Single crowns: 33, Splinted restorations: 65) were included. The overall implant survival rates were 96.9% at implant level and 97.0% at patient level. Veneer chipping was the most common hardware complication. The veneer chipping rates were 19.4% at patient level and 18.4% at implant level. All patients showed acceptable oral hygiene. Thus, the average MBL was 1.19 mm at implant level and 1.15 mm at patient level. Eight implants (8.5%) and six patients (9.2%) were diagnosed with peri-implantitis. Fifty-eight patients (89.2%) were satisfied with the esthetics of the restorations, while 55 patients (84.6%) were satisfied with the function of the restorations. CONCLUSION: Narrow diameter implants could be a predictable treatment option in the long term. High survival rates, high patient satisfaction, acceptable complication rates and marginal bone loss could be achieved. Further long-term studies are needed to evaluate the predictability of NDIs in molar sites.

Survival of Implants Using the Osteotome Technique With or Without Grafting in the Posterior Maxilla: A Systematic Review.

PURPOSE: The aim of this review was to systematically appraise survival rates of implants placed using the osteotome technique with and without grafting in the published literature. MATERIALS AND METHODS: An electronic search was conducted to identify prospective and retrospective studies on osteotome sinus floor elevation published between January 1, 2000 and October 30, 2015. Studies were included that (1) involved use of the osteotome technique with or without grafting; (2) provided data regarding the implant survival rates, residual bone height (RBH), and grafting materials; and (3) reported mean follow-up of at least 1 year after functional loading and included a minimum of 10 patients. The mean weighted cumulative implant survival rates were used to compare the two treatment strategies-grafted or nongrafted. The influence of RBH and implant length on weighted cumulative implant survival was also evaluated. RESULTS: After search and evaluation of the literature according to the inclusion criteria, 34 studies involving 1,977 patients and 3,119 implants were included. Eighty-four out of 102 implant failures documented in the studies occurred within 1 year of functional loading. Statistically significant differences in the cumulative survival rates were found in the graft and nongraft groups (95.89% and 97.30%, respectively; P = .05). In the nongraft group, no statistically significant difference in the cumulative survival rate was found when implants were placed at RBH < 5 mm or ≥ 5 mm (95.04% and 97.63%, respectively; P = .12). In the graft group, however, a statistically significant difference was found when implants were placed at RBH < 5 mm or ≥ 5 mm (92.19% and 97.59%, respectively; P < .01). Significantly lower weighted mean cumulative implant survival rates were found in the shorter (< 8 mm) implant group than in the longer (≥ 8 mm) implant group (83.33% and 96.28%, respectively; P < .01). CONCLUSION: The cumulative survival rates were significantly higher in the nongraft group than in the graft group. Early failures (< 1 year functional loading) accounted for the vast majority of the implant failures. The cumulative survival rates in the graft group were significantly lower when the RBH was < 5 mm, while the cumulative survival rates in the nongraft group demonstrated no statistically significant difference based on RBH. Shorter (< 8 mm) implants demonstrated significantly lower cumulative survival rates than longer implants.

Distributions of Synergistetes in clinically-healthy and diseased periodontal and peri-implant niches.

Bacterial taxa belonging to the phylum Synergistetes are commonly detected within diseased periodontal niches, but are rarely found within healthy oral sites. However, as they typically constitute a minor fraction of the oral microbiota, their precise distributions and disease-associations remain to be fully established. Here, we surveyed the Synergistetes taxa present within individual periodontal/subgingival and peri-implant/submucosal sites, within Chinese subjects (n = 18) affected by both peri-implantitis and periodontitis. Four individual, clinically-distinct sites were analyzed in each patient: healthy sulcus; periodontitis lesion; healthy peri-implant space; peri-implantitis lesion. We employed a clone library-based approach, using PCR-primers that specifically amplified ca. 650bp regions of the 16S rRNA gene from oral cluster A and B Synergistetes taxa. Twenty-one of the 72 sites (from 12/18 subjects) yielded Synergistetes 16S rRNA PCR products. Sequencing of cloned amplicon libraries yielded 1338 quality-filtered 16S rRNA sequences, which were assigned to 26 Synergistetes operational taxonomic units (OTUs; oral taxon SH01-SH26) using a 98.5% identity cut-off. We identified 25 Synergistetes oral cluster A OTUs (genus Fretibacterium; corresponding to Human Oral Taxon (HOT) numbers 358, 359, 360, 361, 362, 363, 452, and 453), and one oral cluster B OTU (Pyramidobacter piscolens oral taxon SH04, HOT-357). Three OTUs predominated: Fretibacterium oral taxon SH01 (HOT-360), Fretibacterium oral taxon SH02 (HOT-452), and Fretibacterium fastidiosum oral taxon SH03 (HOT-363). The Synergistetes community compositions within the respective periodontal and peri-implant sites were variable and complex, and no statistically-significant correlations could be established. However, the detection frequency of F. fastidiosum SH03 and Fretibacterium oral taxon SH01 were both positively associated with plaque index at healthy subgingival sites. Taken together, our results show that diverse Synergistetes populations inhabit both diseased and healthy periodontal and peri-implant niches, with considerable site-to-site variations in composition occurring within the same oral cavity.

Resonance frequency analysis of implants placed with osteotome sinus floor elevation in posterior maxillae.

OBJECTIVES: To test the reliability and validity of implant stability quotient (ISQ) values used for assessment of the condition of bone-to-implant interface in the osteotome sinus floor elevation (OSFE) model and to evaluate the influence of residual bone height (RBH) on ISQ values. MATERIAL AND METHODS: Forty-six Straumann(®) tissue-level SLA implants (Φ4.8 mm*8 mm, wide neck, standard plus) placed in 39 patients applying OSFE without grafting were included in the study. Patients were assigned to three groups based on the RBH with one implant per patient randomly chosen: (1) 2 ≤ RBH < 4 mm (n = 14); (2) 4 ≤ RBH < 6 mm (n = 15); (3) 6 ≤ RBH < 8 mm (n = 10). ISQ values were determined with Osstell ISQ(®) at 0, 2, 4, 8, 12, 16, and 20 weeks postoperation. The reliability of RFA measurements was tested by the degree of dispersion of ISQ values at each time point, and the validity was tested by linear correlation between ISQ and RBH. ISQ values were then compared among groups at all observed time points. RESULTS: The implants achieved a mean ISQ value of 63.6 immediately after surgery and reached a higher ISQ level of 70 after 20 weeks with a dip at 4 weeks. A higher degree of dispersion of ISQ values was observed immediately after surgery compared to the other time points. No significant correlations were found between RBH and ISQ values and no significant difference in ISQ values among groups at all the time points. CONCLUSION: Within the limits of the study, it may be implied that ISQ values are not able to assess the condition of bone-to-implant interface and the role of single RFA measurement in determining loading protocol is questionable.

Transalveolar sinus floor elevation using osteotomes without grafting in severely atrophic maxilla: a 5-year prospective study.

OBJECTIVE: The aim of this study was to assess the clinical success of dental implants placed in severely atrophic maxilla (residual bone height ≤4 mm) using transalveolar sinus floor elevation (TSFE) without grafting. Furthermore, the implant stability during the healing period was also evaluated. MATERIALS AND METHODS: Twenty five generally healthy patients with 37 Straumann(®) Standard Plus SLA implants were included in the study. After a modified Summers TSFE without grafting was performed, the smooth collar was embedded 0.5-1 mm beneath the cortical bone level. Follow-ups were conducted at 12, 36, and 60 months after crown placement. Implant survival rate, resonance frequency analysis (RFA), and clinical and radiographic parameters were evaluated. RESULTS: At 5-year follow-up, 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. The mean value of implant stability quotient (ISQ) ranged from 67.8 to 72.8, and the lowest values were reached at 4 weeks. No significant difference was found with the passage of time in modified plaque index (P = 0.92), pocket probing depth (P = 0.34), and modified bleeding index (P = 0.4). The average residual bone height was 2.81 mm (SD: 0.74 mm) in this study. The average crestal bone loss (CBL) significantly increased from 0.83 mm at 1-year examination to 1.47 mm at 3-year examination (P < 0.001). The average CBL remained stable at years 3 and 5 (1.47 vs. 1.54 mm, P = 0.083). CONCLUSION: According to the current evidence, it is feasible to place cylindrical implants in severely atrophic maxilla. High survival rate could be achieved following TSFE without grafting at least within 5-year follow-up.

Periodontal and peri-implant microbiota in patients with healthy and inflamed periodontal and peri-implant tissues.

OBJECTIVE: To compare the prevalence and levels of six bacterial pathogens within the subgingival/submucosal microbiota at teeth versus implants with various clinical conditions. MATERIAL AND METHODS: Twenty-two Chinese were included. Four subgingival/submucosal sites were selected for microbiological sampling within each subject, that is, (1) healthy peri-implant tissues; (2) peri-implantitis [PPD ≥ 5 mm, presence of bleeding on probing (BOP) and confirmed radiographic bone loss]; (3) healthy gingiva; and (4) periodontitis (PPD ≥4 mm). Subgingival/submucosal plaque was sampled using paper points. Quantitative real-time polymerase chain reaction (q-PCR) was used to quantify six pathogens, including Porphyromonas gingivalis (P.g.), Treponema denticola (T.d.), Aggregatibacter actinomycetemcomitans (A.a.), Fusobacterium nucleatum (F.n.), Prevotella intermedia (P.i.), and Staphylococcus aureus (S.a.). Counts were log10-transformed. RESULTS: The most commonly detected species were S. a. and F. n., while A. a. and. P. i. had the lowest detection frequency. The detection frequencies of diseased tooth or implant sites for each of the six target species were either equal to or higher than the respective frequencies at the corresponding healthy sites. There were no statistically significant differences for any of the species or clinical sites (P > 0.05, Cochran's Q test). No statistically significant differences in the bacterial loads were found among the four clinical sites; with the exception of F. nucleatum. This was more abundant in periodontitis sites (P = 0.023, Friedman's 2-way anova). Both periodontal and peri-implant sites, irrespective of their health status, were revealed to harbor S. aureus cells. The log10-transformed loads of S. aureus were approximately 3.5 within each of the clinical sites (P = 0.232). This was the highest of the six species analyzed. CONCLUSIONS: Within the same subjects, putative periodontal pathogens were common to both periodontal and peri-implant sites irrespective of health status. The prevalence and levels of P. gingivalis and F. nucleatum were significantly associated with periodontitis, but not with peri-implantitis. A. actinomycetemcomitans was associated with both disease conditions, periodontitis and peri-implantitis, but not with either gingival or mucosal health.

Clinical evaluation of short 6-mm implants alone, short 8-mm implants combined with osteotome sinus floor elevation and standard 10-mm implants combined with osteotome sinus floor elevation in posterior maxillae: study protocol for a randomized controlled trial.

BACKGROUND: Nowadays, short dental implants are being increasingly applied in extremely resorbed posterior regions. The recent studies have indicated that short implants present a similar success rate to conventional implants. It is assumed that short implants can avoid additional surgical morbidity and are less technically demanding. However, high-quality evidence (≥ Ib: evidence from at least one randomized controlled trial) on comparing the clinical outcome of short implants and longer implants combined with osteotome sinus floor elevation (OSFE) technique is limited. METHODS/DESIGN: The proposed study is designed as a prospective single-center, three-arm parallel group, randomized controlled trial. We plan to enroll 150 patients in need of dental implant treatment in the posterior maxilla. The inclusion criteria include: age ≧ 18 years, partial edentulism in the posterior maxilla for at least 3 months from tooth loss, residual bone height ranging from 6 to 8 mm, sufficient bone width (≥ 6 mm) in the edentulous region. The patients will be divided into three groups according to a table of random numbers: group 1: short implants (6 mm) alone; group 2: short implants (8 mm) combined with osteotome sinus floor elevation (OSFE); group 3: standard implants (10 mm) combined with OSFE. The assignment will be concealed from the clinical operators until the beginning of implant surgery. The outcome examiners and patients will be kept blinded to the assignment. Implant survival rates, implant success rates, complications, resonance frequency analysis (RFA) measurements, marginal bone level, treatment time and patient-reported outcome (visual analogue scale for intraoperative discomfort and postoperative pain) will be recorded. Clinical re-evaluations will be performed at 12, 24, 36 and 60 months after crown placement. DISCUSSION: The results of the trial will support better decision-making for dental implant treatment in atrophic maxillary ridges. If favorable, the use of short implants may avoid adjunct procedures used for implant insertion, thus reducing operative time, complexity and postoperative discomfort. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02350075 (registered on 17 February 2015).

Esthetic outcome and alterations of soft tissue around single implant crowns: a 2-year prospective study.

OBJECTIVE: The aim of this prospective study was to assess the esthetic outcome and alterations of peri-implant soft tissue using tissue-level implants. Furthermore, the influencing factors, including grafting and gingival biotype, of esthetic outcome of peri-implant soft tissue were also evaluated. MATERIALS AND METHODS: Of 38 patients with single missing anterior tooth in maxilla were treated with a Straumann (®) Standard Plus SLA implant. Bone augmentation was performed in 24 patients. Follow-up was conducted at 12 and 24 months after definitive crowns placement. Esthetic outcome using the pink esthetic score/white esthetic score (PES/WES) and clinical parameters were evaluated. RESULTS: The mean PES/WES value at baseline, 1-year, and 2-year examination was 13.79, 14.87, and 14.96. Significant improvement was found between baseline and 1-year examination (P < 0.01). And the improvement between 1-year and 2-year examination was not significant (P = 0.40). The mean PES changing value in patients with thick biotype was significantly higher than those with thin biotype at 2-year after definitive crowns placement (P = 0.03). Graft procedure had an unfavorable effect on mean PES value both at baseline and at follow-up (P < 0.01). No implants were lost at 2-year examination. Three patients experienced peri-implant infection. No significant difference was found with the passage of time in modified plaque index (mPI), probing pocket depth (PPD), and modified bleeding index (mBI). CONCLUSION: According to the present prospective clinical study, it can be concluded that it is feasible to use tissue-level implant to support single crowns in esthetic area. Favorable short-term esthetic outcome and stability of soft tissue around single implant crowns can be expected in patients with or without graft. However, graft procedures might have an unfavorable effect on the esthetic outcome. Gingival biotype can be considered as prognostic factor for esthetic outcome. RCTs with long-term follow-up are needed to provide evidence for the long-term stability of peri-implant soft tissue using tissue-level implant systems.

Osteotome sinus floor elevation with and without grafting: an animal study in Labrador dogs.

AIM: To evaluate implant stability and histological outcomes after osteotome sinus floor elevation (OSFE) procedure, and to compare new bone formation and implant osseointegration with and without grafting. MATERIAL AND METHODS: OSFE with simultaneous implant placement was conducted bilaterally on 6 Labrador dogs. Twenty-four implants were placed. The right side sinus (Group 1) was grafted with biphasic calcium phosphate (BCP), whereas the left side (Group 2) was left without any grafting materials. The animals were euthanized 8 and 24 weeks after surgery for histological and histomorphometric assessment. Bone-to-implant contact (BIC%), alveolar bone height (ABH), bone density (BD) and grafting material density (GMD) were measured. The implant stability (ISQ) was assessed using resonance frequency analysis (RFA) at implant placement and 1, 2, 4, 8, 12, 24 weeks after surgery. RESULTS: Endo-sinus new bone with direct contact to implant surface were observed in two groups at both time points. ABH showed no difference between groups at both time points. BIC% and BD in Group 2 (40.05%, 35.90%) was higher than those in Group 1 (23.30%,25.59%) at 24 weeks. Significant shrinkage of grafting material was seen in Group 1. The GMD in Group 1 at 8 weeks was 24.35%, while it dropped to 19.90% at 24 weeks. The changing pattern of ISQ for both groups were similar. CONCLUSIONS: Spontaneous new bone formation and better bone-to-implant contact were found for OSFE without grafting. The grafting material application during OSFE procedure showed no advantages in histological results.

Esthetic outcome of single implant crowns following type 1 and type 3 implant placement: a systematic review.

OBJECTIVE: The aim of the current review was to systematically appraise the esthetic outcome of soft tissue around single implant crowns following type 1 and type 3 implants placement in published dental literature. MATERIALS AND METHODS: A PubMed, Embase, and the Cochrane Central Register of Controlled Trials search up to March 2013 was conducted for articles published in the dental literature and limited to human trials with no language restricted. Furthermore, the reference lists of related articles were systematically screened, and additional manual searches were also performed. The primary outcome was pink esthetics score (PES). RESULTS: The electronic search in the database of PubMed, Embase, and the Cohrane Central Register of Controlled Trials resulted in the identification of 463 titles. These titles were initially screened by the two independent reviewers for possible inclusion. Screening the abstracts and titles led to 28 articles for future full-text consideration. From these articles, 18 studies were excluded. Manual search identified one article. After quality assessment, eight studies were included in this review. This review showed that no significant difference of PES index could be found between type 1 and type 3 implant placement. CONCLUSION: According to the current evidence, short-term esthetic outcomes of peri-implant soft tissue did not show significant difference following type 1 and type 3 implants placement with well-selected patients. However, caution should be taken for clinicians to extrapolate this result to all types of patients, as more randomized clinical trials are needed for long-term soft-tissue esthetic outcome in patients with high esthetic risk following type 1 implant placement. PES frequency, peri-implant condition and other risk factors for peri-implantitis are recommended to be reported for future studies.

Subgingival microbiota of Sri Lankan tea labourers naïve to oral hygiene measures.

AIM: To characterize the subgingival microbiota within a cohort of adult males (n = 32) naïve to oral hygiene practices, and to compare the composition of bacterial taxa present in periodontal sites with various probing depths. MATERIAL AND METHODS: Subgingival plaque samples were collected from single shallow pocket [pocket probing depth (PPD)≤3 mm] and deep pocket (PPD≥6 mm) sites from each subject. A polymerase chain reaction based strategy was used to construct a clone library of 16S ribosomal RNA (rRNA) genes for each site. The sequences of ca. 30-60 plasmid clones were determined for each site to identify resident taxa. Microbial composition was compared using a variety of statistical and bioinformatics approaches. RESULTS: A total of 1887 cloned 16S rRNA gene sequences were analysed, which were assigned to 318 operational taxonomic units (98% identity cut-off). The subgingival microbiota was dominated by Firmicutes (69.8%), Proteobacteria (16.3%), and Fusobacteria (8.0%). The overall composition of microbial communities in shallow sites was significantly different from those within deep sites (∫-Libshuff, p < 0.001). CONCLUSIONS: A taxonomically diverse subgingival microbiota was present within this cohort; however, the structures of the microbial communities present in the respective subjects exhibited limited variation. Deep and shallow sites contained notably different microbial compositions, but this was not correlated with the rate of periodontal progression.

Osteotome sinus floor elevation with or without grafting: a 3-year randomized controlled clinical trial.

AIMS: To evaluate the clinical and radiographic results of dental implant placed using osteotome sinus floor elevation (OSFE) with and without simultaneous grafting. MATERIALS & METHODS: Forty-five patients were randomly assigned into two groups: Group1: OSFE with deproteinized bovine bone mineral (DBBM) mixed with autogenous bone chips, and Group2: OSFE without grafting. The endo-sinus bone gain (ESBG) was assessed on radiographs at 6, 12, 24, 36 months following surgery as primary outcome measurement. Implant survivals and marginal bone loss (MBL) were assessed as secondary outcome measurements. RESULTS: Twenty-one implants in Group1 and 20 implants in Group2 were analysed. The residual bone height (RBH) was 4.63 ± 1.31 mm in average (4.67 ± 1.18 mm for Group1 and 4.58 ± 1.47 mm for Group2). The 3-year cumulative survival rates of implants were 95.2% for Group1 and 95.0% for Group2. The ESBG in Group1 reduced from 5.66 ± 0.99 mm at 6 months to 3.17 ± 1.95 mm at 36 months, whereas the ESBG in Group2 increased from 2.06 ± 1.01 mm at 6 months to 3.07 ± 1.68 mm at 36 months. The MBL after 3 years was 1.33 ± 0.46 mm in Group1 and 1.38 ± 0.23 mm in Group2. CONCLUSIONS: OSFE and simultaneous implant installation with and without grafting both resulted in predictable results. The application of grafting materials has no significant advantage in terms of clinical success.

Long-term outcomes of short dental implants supporting single crowns in posterior region: a clinical retrospective study of 5-10 years.

OBJECTIVE: Aimed to evaluate the long-term clinical and radiographic outcomes of short implants supporting single crowns in the posterior regions. MATERIAL AND METHODS: A retrospective study design was adopted. The clinical and radiographic data of 231 short implants (intra-bony length ≤8 mm) supporting single crowns in 168 patients, were collected after 5-10 (mean 7.22) years' follow-up. Implant and prosthesis failures, peri-implant marginal bone loss, biological and technical complications were evaluated. The influence factors on implant failure were studied. RESULTS: In total 4 implants and 11 prostheses failed. The 10-year (5-year) cumulative survival rate was 98.3% (98.7%) for implant-based analysis and 97.6% (98.2%) for patient-based analysis. The short implants placed in type IV bone yielded more failures than in type I-III and presented a survival rate of 94.0%. The 10-year survival rate of the prostheses was 95.2%. The mean marginal bone loss between implant installation and the 10 years' follow-up visit was 0.63 ± 0.68 mm. The marginal bone loss between the first and 5th year was minimal (0.05 ± 0.10mm and not statistically significant). 18 (7.8%) implants were exposed to biological complications, whereas 29 (12.6%) implants were involved in technical complications. CONCLUSIONS: High survival rates for both the implants and the prostheses could be achieved after 5-10 years for short implants supporting single crowns, without severe marginal bone loss and complications. One may conclude that a single crown supported by a short implant is a predictable treatment modality. However, short implants in type IV bone sites should be applied with caution.

Papillae alterations around single-implant restorations in the anterior maxillae: thick versus thin mucosa.

To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration. According to the inclusion criteria, 32 patients subjected to implant-supported single-tooth restorations in anterior maxillae were included. The patients were assigned to two groups according to the mucosal thickness: (i) group 1, 1.5 mm s mucosal thickness 3 mm; and (ii) group 2, 3 mm

The roles of extracellular signal-regulated kinase 1/2 pathway in regulating osteogenic differentiation of murine preosteoblasts MC3T3-E1 cells on roughened titanium surfaces.

Surface roughness of titanium-based implants may enhance osteogenic differentiation of cells in vitro and bone-to-implant contact in vivo. Nevertheless, how surface roughness regulates the signaling pathway of osteoblasts is little understood. The study intended to investigate specifically the roles of extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in regulating osteogenic differentiation of MC3T3-E1 murine preosteoblast cells on Ti surfaces. Substrates applied were two groups of titanium disks: (1) sand-blasted and acid-etched rough surfaces (SLA) and (2) smooth pretreated Ti surfaces (PT). Surface morphology of the two groups was examined by scanning electron microscope, and cell morphology cultured on Ti disks was observed by confocal microscope. The levels of alkaline phosphatase (ALP) activity and calcium deposition were measured and compared between the two groups. Real-time polymerase chain reaction was applied to detect the expression levels of osteogenic genes including runt related protein 2 (Runx2), osterix (OSX), osteocalcin (OCN) and osteoprotegerin (OPN) of the cells cultured on the two groups of substrates and on SLA surfaces treated with ERK1/2 inhibitor, PD98095. ERK1/2 activities in MC3T3-T1 cells were measured by Western-blotting on the two surfaces with or without PD98095. Cells cultured on rougher SLA surfaces displayed a more differentiated morphology. ALP activities at 7 days and 14 days and the calcium deposition at 28 days were significantly higher on SLA surfaces. The expression levels of Runx2, OSX, OPN and OCN were upregulated by the effect of surface roughness and PD98095 further upregulated the expression levels of these osteogenic genes on SLA surfaces. ERK1/2 phosphorylation was continuously inhibited by surface roughness at 2 days, 4 days and 6 days. In contrast, no marked alterations in ERK1/2 phosphorylation on PT surfaces were observed. PT surfaces treated with PD98095 (50 µM) and SLA surfaces without PD98095 both demonstrated reduced ERK1/2 phosphorylation of the cells, and the inhibitive effect of SLA surfaces was milder than that of PD98095. In conclusion, ERK1/2 pathway may be a negative regulator of cell differentiation in a dosage-dependent manner, and the enhancing effect of surface roughness on osteoblastic differentiation may be mediated through inhibiting ERK1/2 pathway.

[Animal study of sensory function of nerve fibers surrounding dental implant].

PURPOSE: To investigate the distribution of sensory nerve fibers in the tissue of peri-implant bone and to study the reconstruction procedure of somatosensory evoked potentials of unloaded dental implant. METHODS: The bilateral 2nd, 3rd and 4th mandibular premolars and the 1st molars were extracted from 3 beagle dogs. Three months later, 4 screw-type implants were inserted. Then 1, 6 and 12 weeks later, the sensory nerve action potential(SNAP) tests were performed. The stimulating electrode was connected to the implant, and the recording electrodes were fixed on the inferior alveolar nerve stem to record the amplitude of SNAP. Then the dogs were sacrificed, and the specimens were prepared for immunohistochemical examination. The SNAP results were statistically analyzed using SPSS17.0 software package. RESULTS: SNAP of the inferior alveolar nerve stem could be recorded following stimulations to each implant. The difference in SNAP amplitudes between the 1-week group and the other two groups was significant (P<0.05) But there was no significant difference between the 6-week and 12-week group. Some NFP-positive nerve fibers were found in the tissues of peri-implant bone. These fibers localized in both the bone marrow space and in the peri-implant fibrous tissues. CONCLUSIONS: Neuroreceptors do exist in the tissue of peri-implant bone, but much less than the periodontal ligament. These neuroreceptors could receive electrical stimulus then evoke SNAP of the inferior alveolar nerve stem. In unloaded condition, the reconstruction of never endings in the peri-implant bone tissue is apparently time-dependent.

[The influence of chemically-modified SLA on bone defect healing around implants in dogs].

PURPOSE: The study was designed to investigate the effect of surface chemical modification on the process of bone defect healing around implants in dogs. METHODS: Six Beagle dogs were used in this study. The mandibular premolars and first molars were extracted bilaterally. Three months after tooth extraction the procedure of implant placement was performed. Four canals with a diameter of 2.8 mm and 10 mm in depth were prepared at the third premolar (P3) and the first molar (M1) sites of both sides of the mandible, of which the coronal 5 mm portion were further widened with the 5.3 mm diameter twist drill. In each side of the mandible one modSLA (chemically-modified SLA) implant and one SLA (sandblasted, large-grit, acid-etched) implant with a diameter of 3.3 mm and 10 mm in length were installed, respectively. Thus, the circumferential defect that was 5mm deep and 1mm wide created between the implant surface and the bony wall. Four implants placed in both sides of the mandible were allowed for non-submerged healing. Two dogs were sacrificed at the week 2, 4 and 8 following implant placement, respectively, and the specimens were prepared and stained with trinitrophenol- fuchsin for histological and histomorphometric analyses to acquire the bone-to-implant contact (BIC%), new bone fill (NBF%) and the distance between the most coronal level of bone-to-implant contact and the bottom of the surgically created bone defect(B-D). Statistical analysis was conducted with SPSS13.0 software package. RESULTS: No implant was loosen or lost during the study. The histomorphometric results demonstrated that new bone formation was observed in the defect region around both groups of implants at all time points and the newly formed bone occurred initially from the apical and lateral bony wall of the defect region, the bone defect almost was filled at week 8. At 2 and 4 weeks of healing, the BIC%, NBF% and B-D values were significantly higher for modSLA implants (P<0.05). At 8 weeks of healing, the difference was not significant (P>0.05). CONCLUSIONS: The SLA implants processed by means of chemically-modified surface treatments exhibit more predictable outcomes than that of SLA implants by promoting the early bone regeneration when inserted into sites with bone defects.

Osteotome sinus floor elevation with or without grafting: a preliminary clinical trial.

OBJECTIVES: This clinical trial aimed (1) to evaluate the predictability of the osteotome sinus floor elevation (OSFE) technique, (2) to study the influence of simultaneous grafting on the clinical success of placing dental implants in the posterior maxilla using OSFE and (3) to observe the bone changes in the elevated space with OSFE without grafting. MATERIAL AND METHODS: Two hundred and eighty Straumann implants were placed in the posterior maxillae of 202 patients using OSFE. One hundred and ninety-one implants were placed in 125 patients without grafting. The implants were allowed to heal for 3-4 months for non-grafted implants and for 6-8 months for grafted cases. For radiographic analyses, periapical and panoramic radiographs were taken of 30 implants at 3 and 9 months to assess the bone changes for the elevated sites without grafting. RESULTS: Two hundred and sixty-eight of 280 implants fulfilling the survival criteria represented a cumulative survival rate of 95.71%. The residual bone height (RBH) was 5.6+/-2.5 mm for the non-grafted group and 4.7+/-2.1 mm for the grafted group. The perforation rate was 4.29%. No significant differences were found between the two groups in RBH, survival rate or membrane perforation rate. The radiographic analyses demonstrated that new bone formation in the elevated sinus was visible and the endo-sinus bone gain was 2.26+/-0.92 mm and 2.66+/-0.87 mm at 3- and 9- month follow-up, respectively. Crestal bone loss (CBL) was 0.89+/-0.5 and 1.2+/-0.48 mm at 3 and 9 months. For the two test groups, RBH did not have a significant influence on the survival of the implants. At the 9-month follow-up, the endo-sinus bone gain and CBL were not significantly correlated to RBH. The implant protrusion length was significantly correlated to the endo-sinus bone gain. CONCLUSIONS: The findings of this study indicated that uneventful osseointegration may be predictable on applying OSFE whether with or without grafting in atrophic posterior maxilla. Spontaneous new bone formation seemed to be expected with implants placed using OSFE without simultaneous grafting.