Automating Periodontal bone loss measurement via dental landmark localisation.

PURPOSE: Periodontitis is the sixth most prevalent disease worldwide and periodontal bone loss (PBL) detection is crucial for its early recognition and establishment of the correct diagnosis and prognosis. Current radiographic assessment by clinicians exhibits substantial interobserver variation. Computer-assisted radiographic assessment can calculate bone loss objectively and aid in early bone loss detection. Understanding the rate of disease progression can guide the choice of treatment and lead to early initiation of periodontal therapy. METHODOLOGY: We propose an end-to-end system that includes a deep neural network with hourglass architecture to predict dental landmarks in single, double and triple rooted teeth using periapical radiographs. We then estimate the PBL and disease severity stage using the predicted landmarks. We also introduce a novel adaptation of MixUp data augmentation that improves the landmark localisation. RESULTS: We evaluate the proposed system using cross-validation on 340 radiographs from 63 patient cases containing 463, 115 and 56 single, double and triple rooted teeth. The landmark localisation achieved Percentage Correct Keypoints (PCK) of 88.9%, 73.9% and 74.4%, respectively, and a combined PCK of 83.3% across all root morphologies, outperforming the next best architecture by 1.7%. When compared to clinicians' visual evaluations of full radiographs, the average PBL error was 10.69%, with a severity stage accuracy of 58%. This simulates current interobserver variation, implying that diverse data could improve accuracy. CONCLUSIONS: The system showed a promising capability to localise landmarks and estimate periodontal bone loss on periapical radiographs. An agreement was found with other literature that non-CEJ (Cemento-Enamel Junction) landmarks are the hardest to localise. Honing the system's clinical pipeline will allow for its use in intervention applications.

Biomechanical Behavior of All-on-4 and M-4 Configurations in an Atrophic Maxilla: A 3D Finite Element Method.

BACKGROUND In edentulous patients, the concept of 4 implants with early loading has been widely used in clinical settings. In the case of bone atrophy in the anterior maxilla, using short implants or an angulated implant may be a good choice for treatment. The occlusal scheme remains a key aspect of All-on-4. The aim of this study was to use the 3-dimensional (3D) finite element method (FEM) to evaluate how different All-on-4 designs for canine-guided and group function occlusion affected the distribution of stress in the atrophic premaxilla. MATERIAL AND METHODS A 3D edentulous maxilla model was created and in 3D FEM, 3 different configurations - M4, All-on-4, and short implant - were modeled by changing the anterior implants and using 2 different occlusal schemes. For each model, the occlusal load was applied to simulate lateral movements. For cortical bone, the maximum and minimum principal stress values were generated, and for ductile materials, von Mises stress values were obtained. RESULTS No significant differences were detected among the models; generally, however, the highest stress values were observed in the M-4 model and the models with short implants. Slightly higher stress values were observed in the group function occlusion group than in the canine-guided occlusion group. CONCLUSIONS To promote better primary stabilization, M-4 or short implant configurations with canine-guided occlusion appear to be preferable for patients who have severe atrophy in the anterior maxilla.

One Abutment One Time: A Multicenter, Prospective, Controlled, Randomized Study.

Aim: (PRIMARY) Assess the changes in bone level (6 and 12 months after implant placement) between the test (definitive abutment (DEF)) and control (healing abutment (HEA)) groups. (SECONDARY) Assess the changes in bone level (6 and 12 months after implant placement) between the 1 mm high abutment group and 2 mm abutment group. Evaluate changes in implant stability recorded with analysis of the resonance frequency (RFA) Osstell system, at 6 and 12 months after implant placement, between the control group (HEA) and test (DEF). For the DEF group, the abutment was placed at the time of the surgery and was never removed. For the HEA group, the abutment was removed three times during the manufacture of the crowns. The abutments used were 1 mm high (Subgroup A) and 2 mm high (Subgroup B). Materials and methods: A total of 147 patients were selected between 54.82 ± 11.92 years old. After implant placement, patients were randomly distributed in the DEF and HEA group. After the implant placement, a periapical radiograph was taken to assess the peri-implant bone level; the same procedure was carried out 6 and 12 months post-placement. To compare the qualitative variables between the groups (HEA/DEF), the Chi-square test was used; for quantitative (MANOVA). Results: After a year, the accumulated bone loss was 0.48 ± 0.71 mm for the HEA group and 0.36 ± 0.79 mm for the DEF group, without statistical significance. Differences were only found due to timing (time) between 0 and 6 months (=0.001) and 0 and 12 months (0.001), with no differences attributable to the study groups (DEF and HEA). The accumulated bone loss (1 year) was 0.45 ± 0.78 mm for the 1 mm abutment group and 0.41 ± 0.70 mm for the 2 mm abutment group (p = 0.02). No differences were observed in implant stability between groups. Conclusions: The "One Abutment-One Time" concept does not reduce peri-implant bone loss compared to the connection-disconnection technique. The height of the abutment does influence bone loss: the higher the abutment, the lower the bone loss.

Comparative Analysis of Peri-Implant Bone Loss in Extra-Short, Short, and Conventional Implants. A 3-Year Retrospective Study.

OBJECTIVE: To evaluate the influence of implant length on marginal bone loss, comparing implants of 4 mm, 6 mm, and >8 mm, supporting two splinted crowns after 36-month functional loading. MATERIALS AND METHODS: this retrospective clinical trial evaluated the peri-implant behavior of splinted crowns (two per case) on pairs of implants of the same length placed in the posterior maxilla (molar area). Implants were divided into three groups according to length (Group 1: extra-short 4 mm; Group 2: short 6 mm; Group 3: conventional length >8 mm). Marginal bone loss was analyzed using standardized periapical radiographs at the time of loading and 36 months later. RESULTS: 24 patients (19 women and 5 men) were divided into three groups, eight rehabilitations per group, in the position of the maxillary first and second molars. The 48 Straumann® Standard Plus (Regular Neck (RN)/Wide Neck (WN)) implants were examined after 36 months of functional loading. Statistical analysis found no significant differences in bone loss between the three groups (p = 0.421). No implant suffered biological complications or implant loss. Long implants were associated with less radiographic bone loss. CONCLUSIONS: extra-short (4 mm); short (6 mm); and conventional length (>8 mm) implants in the posterior maxilla present similar peri-implant bone loss and 100% survival rates in rehabilitation, by means of two splinted crowns after 36 months of functional loading. Implants placed in posterior positions present better bone loss results than implants placed in anterior positions, regardless of the interproximal area where bone loss is measured. Conventional length (>8 mm) implants show better behavior in terms of distal bone loss than short (6 mm) and extra-short (4 mm) implants.

Reliability assessment between clinical attachment loss and alveolar bone level in dental radiographs.

BACKGROUND: The clinical attachment level (CAL) and radiographically assessed bone levels are used to assess the loss of periodontal tissue support in periodontitis, a chronic, multifactorial inflammatory disease of the periodontium. However, few studies have been done to study the relationship between these two parameters. According to our knowledge, this is the first study investigating the relationship between the two measurements using intraclass correlation analysis. AIM: The aim of the study is to investigate the relationship between CAL and radiographically assessed bone level in teeth affected with periodontitis. METHODS: A retrospective cross-sectional study was conducted by selecting a sample of 880 periodontal sites in 104 periodontitis patients, aged 25-60 years. CAL and peri-apical radiographs of the selected sites were obtained from the computerized patient records. The distance from the cemento-enamel junction (CEJ) to the base of the alveolar bone level (ABL) was measured. The data was analyzed using SPSS. RESULTS: Intraclass correlation analysis (ICC) revealed a moderate degree of reliability between CAL and CEJ to ABL measurements. The average ICC was 0.68 with a 95% confidence interval of 0.53-0.77 (p < .001) indicating moderate to good reliability. Comparing the types of teeth, the central incisors, particularly the lower central incisors showed the highest ICC values (ICC: 0.822, CI: 0.77-0.86) indicating good reliability while the premolar and molars showed poor to moderate agreement (Maxillary premolars ICC: 0.464, CI: -0.18-0.74; maxillary first molar ICC: 0.516, CI: -0.154-0.772; mandibular first premolar ICC: 0.662, CI: 0.269-0.782; mandibular first molar ICC: 0.625, CI: 0.31-0.82). A moderate correlation existed between the radiographic and the clinical assessments (r = 0.5, p < .001). CONCLUSION: Despite the fact that significant varying levels of reliability has been found between CAL and radiographic bone level, both the clinical and radiographic examinations should be performed for the accuracy of diagnosis.

Comparative assessment of mouse models for experimental orthodontic tooth movement.

Animal experiments are essential for the elucidation of biological-cellular mechanisms in the context of orthodontic tooth movement (OTM). So far, however, no studies comparatively assess available mouse models regarding their suitability. OTM of first upper molars was induced in C57BL/6 mice either via an elastic band or a NiTi coil spring for three, seven or 12 days. We assessed appliance survival rate, OTM and periodontal bone loss (µCT), root resorptions, osteoclastogenesis (TRAP+ area) and local expression of OTM-related genes (RT-qPCR). Seven days after the elastic bands were inserted, 87% were still in situ, but only 27% after 12 days. Survival rate for the NiTi coil springs was 100% throughout, but 8.9% of the animals did not survive. Both methods induced significant OTM, which was highest after 12 (NiTi spring) and 7 days (band), with a corresponding increase in local gene expression of OTM-related genes and osteoclastogenesis. Periodontal bone loss and root resorptions were not induced at a relevant extent by neither of the two procedures within the experimental periods. To induce reliable OTM in mice beyond 7 days, a NiTi coil spring is the method of choice. The elastic band method is recommended only for short-term yes/no-questions regarding OTM.

Evaluation of PRF Efficiency in the Treatment of Infrabony Defects.

AIM: The present study aimed to investigate the effectiveness of PRF in the treatment of infrabony defects in patients with chronic periodontitis by evaluating the clinical outcome through periodontal depth, clinical attachment level at the baseline, 6 and 9 months post operatively. MATERIAL AND METHODS: Sixty infrabony defects with probing depth ≥ 5 mm were treated. The inclusion criterion was the necessity for surgical bilateral maxillary treatment. By using split-mouth study design, each patient had one side treated with conventional flap surgery and the other side with conventional flap surgery and PRF. Clinical parameters, such as probing depth (PD) and clinical attachment lost (CAL), were recorded in both groups at baseline, 6 and 9 months post operatively. RESULTS: Positive effects for all clinical and radiographic parameters were evident in the group with PRF. Mean PD reduction demonstrated statistically significant greater results in the test group (4.00±1.07 mm) compared to the control one (4.83±0.99 mm), p = 0.003 after 9 months postoperatively. After 9 months, there were better results in the test group compared to the control group for CAL (5.60±1.61 mm, 6.20±1.58 mm), but statistically not significant. CONCLUSION: Additional use of PRF in the conventional surgical treatment of infrabony defects demonstrated better parameters than the open flap debridement alone.

Salivary Osteocalcin as Potential Diagnostic Marker of Periodontal Bone Destruction among Smokers.

: The objective of the study was to assess the levels and diagnostic accuracy of salivary osteocalcin (OC), osteonectin (ON), and deoxypyridinoline-containing degradation fragment of the C-terminal telopeptide region of type I collagen (CTX) in adult smokers with periodontal bone destruction. Towards this, ninety systemically healthy patients (groups I: healthy, II: periodontitis with non-smokers, and III: periodontitis with current smokers) were included in the study. The results showed a positive correlation (weak to moderate) was observed for OC, ON, and CTX with probing pocket depth (PPD; r = 0.40, 0.32, and 0.36) and alveolar bone loss (BL; r = 0.58, 0.38, and 0.51) (p < 0.01). Smoker periodontitis was best discriminated from healthy controls using 15.25 ng/mL of OC (AUC: 0.870; 95% CI: 0.757-0.943; YI (Youden Index): 0.693; p < 0.0001). However, with a cut-off of BL at 33.33%, 19.24 ng/mL of salivary OC gave the best discrimination (AUC: 0.809; 95% CI: 0.686-0.900; Se: 80.0%; Sp: 73.47%, and YI: 0.534). A 16.45 ng/mL amount of OC gave excellent discrimination (AUC: 0.811; 95% CI: 0.688-0.901; Se: 92.31%; Sp: 65.22%, and YI: 0.575) among healthy and smoker periodontitis when PD at 6mm was considered as cut-off. Conclusion: The best discrimination between healthy controls and smoker periodontitis was obtained at 15.25 ng/mL of salivary OC.

Impact of periodontal treatment on the RANKL/OPG ratio in crevicular fluid.

AIM: Alveolar resorption is one of the most important events in periodontitis. Osteoclast activity is regulated by the ratio between receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). The aim of this study was to evaluate changes in the RANKL/OPG ratio in crevicular fluid after periodontal treatment. MATERIAL AND METHODS: A total of 15 patients with periodontitis were included in the study group. Samples were collected from an area with active periodontitis and a healthy area. The RANKL and OPG levels were measured before and after periodontal scaling and root planing (SRP) treatment. The study group was compared to the control group, which included 10 patients without periodontitis. ID Clinicaltrial.gov: NCT03787875. RESULTS: A decrease in the RANKL level was found in areas with active periodontitis after periodontal treatment, but no change in the OPG level was observed. Therefore, the treatment induced a decrease in the RANKL/OPG ratio in sites with destructive periodontal activity. CONCLUSIONS: Periodontal treatment acts on the RANKL/OPG ratio by decreasing osteoclastogenesis. These results encourage the use of these molecules for periodontal diagnosis, monitoring and treatment. ID CLINICALTRIAL.GOV: NCT03787875.

Early-predictors of marginal bone loss around morse taper connection implants loaded with single crowns: A prospective longitudinal study.

BACKGROUND AND OBJECTIVE: Few studies estimated the joint effect of implant design (length and diameter), peri-implant, and occlusal variables on early marginal bone loss. The monitoring of these factors during the first year after implant loading may be effective in preventing early implant failure. This prospective longitudinal study aimed to identify early-predictors of marginal bone loss around morse-tapered connection implants 12 months after implant loading. METHODS: Participants (n = 33) received 109 morse taper implants inserted subcrestally (diameter: 3.5 to 5 mm, length: 6 to 15 mm) loaded with single crowns. Implants were radiographically examined at the implant placement (baseline) and 12 months after prosthetic loading. Implant, peri-implant, and occlusal-related independent variables were analyzed by decision tree analysis. Mixed-effects multilevel analysis was used to estimate adjusted predictive values of marginal bone loss based on the early-predictors identified in decision tree analysis. RESULTS: Higher marginal bone loss was observed at mesial (mean of 0.87 mm; ranged from 0.5 to 1.19) than at distal sites (mean of 0.73 mm; ranged from 0.4 to 1.12 mm). The predictive model revealed of the largest marginal bone loss in association with cement-retained prostheses, a platform diameter of 3.5 mm, papilla sizes up to 2 mm, keratinized mucosa width inferior to 3 mm, implant lengths above 8.5 mm, inadequate occlusal relations, presence of bleeding on probing and deep peri-implant pocket. CONCLUSION: As implant dimensions, peri-implant and occlusal-related factors were associated with early marginal bone loss around morse taper implant, intervention in these factors might prevent early marginal bone loss.

OCT-Based Periodontal Inspection Framework.

Periodontal diagnosis requires discovery of the relations among teeth, gingiva (i.e., gums), and alveolar bones, but alveolar bones are inside gingiva and not visible for inspection. Traditional probe examination causes pain, and X-ray based examination is not suited for frequent inspection. This work develops an automatic non-invasive periodontal inspection framework based on gum penetrative Optical Coherence Tomography (OCT), which can be frequently applied without high radiation. We sum up interference responses of all penetration depths for all shooting directions respectively to form the shooting amplitude projection. Because the reaching interference strength decays exponentially with tissues' penetration depth, this projection mainly reveals the responses of the top most gingiva or teeth. Since gingiva and teeth have different air-tissue responses, the gumline, revealing itself as an obvious boundary between teeth and gingiva, is the basis line for periodontal inspection. Our system can also automatically identify regions of gingiva, teeth, and alveolar bones from slices of the cross-sectional volume. Although deep networks can successfully and possibly segment noisy maps, reducing the number of manually labeled maps for training is critical for our framework. In order to enhance the effectiveness and efficiency of training and classification, we adjust Snake segmentation to consider neighboring slices in order to locate those regions possibly containing gingiva-teeth and gingiva-alveolar boundaries. Additionally, we also adapt a truncated direct logarithm based on the Snake-segmented region for intensity quantization to emphasize these boundaries for easier identification. Later, the alveolar-gingiva boundary point directly under the gumline is the desired alveolar sample, and we can measure the distance between the gumline and alveolar line for visualization and direct periodontal inspection. At the end, we experimentally verify our choice in intensity quantization and boundary identification against several other algorithms while applying the framework to locate gumline and alveolar line in vivo data successfully.

Evaluation of Alveolar Bone on Dental Implant Treatment using Cone Beam Computed Tomography

Objective: To observe the outcomes of dental implant treatment based on the evaluation of bone conditions using Cone Beam Computed Tomography (CBCT). Material and Methods: A total of 31 dental implants were collected for the present study. Subsequently, mesial and distal bone losses were examined, while buccal and lingual bone thickness were measured at 7 levels. Evaluation and interpretation of CBCT results was performed by 3 independent examiners. Results: The average of mesial bone loss was 1.08 mm and 1.36 mm on distal bone. Every dental implant had lingual/palatal bone on level 1 to 3, only 1 (6.5%) didn't have bone on level 4, 3 implants (9.7%) had no bone at level 5 and 6, and 22 implants (74.2%) had no bone at level 7/implant platform. There were 8 implants (25.8%) didn't have buccal bone at level 7, only 1 implant (3.2%) didn't have buccal bone at level 2,4,5 and 6, and there were 2 implants (6.5%) had no buccal bone on level 3. Dehiscence / fenestration can be seen on 90% of the implant subjects. Conclusion: These bone loss condition could be consequence of several factors such as infection, diagnosis, treatment plan, and operator's surgery skills. The implants that placed without CBCT could lead to operator miscalculation on bone condition, therefore in moderate to advanced cases, the use of CBCT should be mandatory for treatment plan.

Diagnostic accuracy of the implant stability quotient in monitoring progressive peri-implant bone loss: An experimental study in dogs.

OBJECTIVES: To investigate the impact of progressive bone loss in an experimental peri-implantitis model in the dog upon the implant stability quotient (ISQ) measured in the course of induced and spontaneous conditions of disease, and to evaluate the association between the clinical parameters and ISQ. MATERIALS AND METHODS: Seventy-two implants were placed in 12 Beagle dogs. Of these, 36 implants in six dogs were assessed during ligature-induced peri-implantitis (three timepoints) and at one timepoint following a period of spontaneous progression. The ISQ was recorded using resonance frequency analysis (RFA). Furthermore, the clinical peri-implant parameters were registered at four sites per implant at each timepoint. Marginal bone loss (MBL) was determined using computed tomography at four sites per implant and bone-to-implant contact (BIC) was assessed from histological samples. A linear regression model was estimated by generalized estimation equations (GEEs) in order to study the MBL-ISQ values at each measurement timepoint. Pearson's correlation test was applied. RESULTS: None of the implants failed during the study period. At implant level, a strong negative correlation was found for all timepoints between ISQ and MBL (r = -0.58; p < 0.001). Accordingly, as follow-up progressed, lower ISQ and higher MBL values were observed. A prediction of MBL depending on the ISQ values and timepoints showed a decrease in one ISQ unit to be related to ~1 mm of MBL. Likewise, a statistically significant correlation was found between BIC and ISQ evaluated after spontaneous chronification of peri-implantitis (r = 0.34; p = 0.04). Nevertheless, the ISQ values failed to correlate to any of the clinical parameters recorded. CONCLUSION: Resonance frequency analysis seems accurate in diagnosing progressive bone loss, as a statistically significant decrease in ISQ was recorded in the course of peri-implant disease. Nevertheless, the clinical relevance of this observation as a diagnostic tool is debatable, since implant stability remains high.

Effects of theaflavins on tissue inflammation and bone resorption on experimental periodontitis in rats.

BACKGROUND AND OBJECTIVE: Theaflavins (TFs), the major polyphenol in black tea, have the ability to reduce inflammation and bone resorption. The aim of this study was to evaluate the effects of TFs on experimental periodontitis in rats. MATERIAL AND METHODS: Thirty rats were divided into five groups: Control (glycerol application without ligation), Ligature (glycerol application with ligation), TF1 (1 mg/mL TF application with ligation), TF10 (10 mg/mL TF application with ligation), and TF100 (100 mg/mL TF application with ligation). To induce experimental periodontitis, ligatures were placed around maxillary first molars bilaterally. After ligature placement, 100 µL glycerol or TFs were topically applied to the rats daily, and rats were euthanized 7 days after ligature placement. Micro-computed tomography was used to measure bone resorption in the left side of the maxilla, and quantitative polymerase chain reaction was used to measure the expression of interleukin (IL)-6, growth-regulated gene product/cytokine-induced neutrophil chemoattractant (Gro/Cinc-1, rat equivalent of IL-8), matrix metalloproteinase-9 (Mmp-9), receptor activator of nuclear factor-kappa Β ligand (Rankl), osteoprotegerin (Opg), and the Rankl/Opg ratio in gingival tissue. With tissue from the right side of the maxilla, hematoxylin and eosin staining was used for histological analysis, immunohistochemical staining for leukocyte common antigen (CD45) was used to assess inflammation, and tartrate-resistant acid phosphatase (TRAP) staining was used to observe the number of osteoclasts. RESULTS: The TF10 and TF100 groups, but not the TF1 group, had significant inhibition of alveolar bone loss, reduction in inflammatory cell infiltration in the periodontium, and significantly reduced numbers of CD45-positive cells and TRAP-positive osteoclasts compared with the Ligature group. Correspondingly, the TF10 and TF100 groups had significantly downregulated gene expression of IL-6, Gro/Cinc-1(IL-8), Mmp-9, and Rankl, but not of Opg. Consequently, Rankl/Opg expression was significantly increased in the Ligation group but was attenuated in the TF10 and TF100 groups. CONCLUSION: The results of this study suggest that topical application of TFs may reduce inflammation and bone resorption in experimental periodontitis. Therefore, TFs have therapeutic potential in the treatment of periodontal disease.

Comparison of Marginal Bone Loss Between Implants with Internal and External Connections: A Systematic Review.

PURPOSE: The objective of this systematic review was to compare the loss of marginal bone between implants with internal and external connections by analyzing results reported in studies published after 2010. MATERIALS AND METHODS: A literature search in MEDLINE with the keywords "dental implant connections, external internal implant connection, bone loss implant designs, internal and external connection implant studies in humans" was conducted. Clinical trials on human beings, comparing both connections and published in English, from 2010 to 2016 were selected. Their methodologic quality was assessed using the Jadad scale. RESULTS: From the initial search, 415 articles were obtained; 32 were chosen as potentially relevant based on their titles and abstracts. Among them, only 10 finally met the inclusion criteria. A total of 1,523 patients with 3,965 implants were analyzed. Six out of 10 studies observed that internal connections showed significantly less bone loss compared with external connections. The remaining four articles did not find statistically significant differences between the two connections. CONCLUSION: According to this systematic review and considering its limitation due to the degree of heterogeneity between the included studies, both internal and external connections present high survival rates. To assess whether marginal bone loss differs significantly between the two connections, more homogenous clinical studies are needed with identical implant characteristics, larger samples, and longer follow-up periods. Studies included in this review and characterized by long-term follow-ups showed that the external connection is a reliable connection on a long-term basis.

Diagnostic performance of cone beam computed tomography in assessing peri-implant bone loss: A systematic review.

OBJECTIVES: To evaluate the diagnostic performance of cone beam computed tomography (CBCT) in the assessment of peri-implant bone loss and analyze its influencing factors. MATERIALS AND METHODS: Clinical and preclinical studies reporting diagnostic outcomes of CBCT imaging of peri-implant bone loss compared to direct reference measurements were sought by searching five electronic databases, PubMed, MEDLINE, EMBASE, Web of Science, and CINAHL Plus, and OpenGrey. QUADAS-2 criteria were adapted for quality analysis of the included studies. A qualitative synthesis was performed. Two meta-analysis models (random-effects and mixed-effects) summarized the area under receiver operating characteristic (AUC) curve observations reported in the selected studies. The mixed-effects meta-analysis model evaluated three possible influencing factors, "defect type," "defect size," and "study effect." RESULTS: The initial search yielded 3,716 titles, from which 18 studies (13 in vitro and 5 animal) were included. Diagnostic accuracy of CBCT was fair to excellent in detecting in vitro circumferential-intrabony and fenestration defects, but moderate to low for peri-implant dehiscences, and tended to be higher for larger defect sizes. Both, over- and underestimation of linear measurements were reported for the animal models. The meta-analyses included 37 AUC observations from eight studies. The random-effects model showed significant heterogeneity. The mixed-effects model exhibited also significant but lower heterogeneity, and "defect type" and "study effect" significantly influenced the variability of AUC observations. CONCLUSION: In vitro, CBCT performs well in detecting peri-implant circumferential-intrabony or fenestration defects but less in depicting dehiscences. Influencing factors due to other site-related and technical parameters on the diagnostic outcome need to be addressed further in the future studies.

Virtually guided alveolar ridge reduction combined with computer-aided implant placement for a bimaxillary implant-supported rehabilitation: A clinical report.

Insufficient crown height space, particularly in the interforaminal region of edentulous ridges with knife-edge morphology, may prevent successful prosthetic rehabilitation. Such conditions require osteoplasty, which might complicate computer-guided implant placement. This clinical report illustrates the treatment of a patient with complete edentulism rehabilitated with a mandibular implant-supported fixed dental prosthesis by using a virtually guided approach. Both alveolar ridge reduction and prosthetically driven implant insertions were computer-guided by surgical stents to increase accuracy and predictability. This approach enabled the immediate loading of the implants with an interim prosthesis before the delivery of a definitive screw-retained fixed prosthesis. At the 1-year follow-up visit, clinical and radiographic examination revealed a stable outcome.

[Establishment of rat model with diabetes mellitus and concomitant periodontitis and the carotid artery lesions in the model rats].

Objectives: To establish SD rat model with type 2 diabetes mellitus (DM) and concomitant chronic periodontitis (CP) and to evaluate the influence of periodontitis on the vascular lesions of type 2 diabetes rats. Methods: Totally 241 clean level SD rats were randomly divided into four groups, group A (normal control, NC, n=27), group B (DM, n=34), group C (CP, n=90) and group D (DM+CP, n=90). The rats of DM group were fed with high-fat and high-sugar diet for 8 to 10 weeks, and then were multiply injected with small dose streptozotocin under the condition of ice bath. Blood sugar levels after the injection were dynamically monitored at 72 h, 1 week, 2 weeks and 4 weeks, respectively. The CP model was established by means of ligation. Bilateral maxillary first and second molars were selected and ligated using 0.2 mm orthodontic wires binding with 4-0 surgical suture soaked with Porphyromonas gingivalis (Pg) suspension. After a period of 14 weeks, all the rats were put to death. Maxillary samples were subjected to methylene blue staining to observe alveolar bone loss. Bilateral carotid artery specimens were collected. The left carotid artery specimens were used to detect the prevalence of Pg using quantitative real-time PCR. The right carotid artery specimens were used to observe pathological changes. Results: Blood sugar levels of rats in group B and D increased and changed sharply after Streptozotocin injection with in 1 week. Symptoms of 'more drink, more food and body weight loss' appeared. The fasting blood glucose (FBG) was more than 7.8 mmol/L and (or) the random blood glucose (RBG) was more than 17.8 mmol/L. Both FBG and RBG became stable after 2 to 3 weeks. Levels of HbA1C in group B and D ([7.32±0.45]%, [9.41±0.45]%) were significantly higher than that of group A ([4.02±0.45]%) (P<0.01). Rats of group D were observed the most severe bone loss showing wider interdental space and furcation involvement. Pathological results of carotid artery tissues of group D showed the worst lesions including thinning and calcification of vessel walls, and breaking down or disappearance of elastic fibers. The prevalences of DNA of Pg in groups of A, B, C and D were 3/7, 3/7, 6/7 and 7/7, respectively. The bacteria numbers detected by quantitative real-time PCR in groups C and D were significantly higher than that of groups A and B (P<0.01). Conclusions: Rat model of type 2 DM with periodontitis was successfully established in the present study. Carotid artery specimens from DM+CP model rats showed typical vascular lesions such as calcification and fiber disorders. Pg was found in all carotid specimens and the highest bacteria numbers were detected in the composite model rats. The Pg might play a role in the progress of diabetes vascular lesions.