Books

Purpose: There is limited evidence available on the influence of location on bone density in the maxilla. Therefore, this study was aimed at comparing the microarchitecture of bone harvested from different nonatrophic maxillary locations. Materials and Methods: A total of 37 partially edentulous subjects (aged 48.15 ± 15.85 years) were included in the study. A bone core biopsy specimen was obtained from one site per patient at the planned implant surgery location. Thirty-four specimens were used for microcomputed tomography (micro-CT) analysis. Mann-Whitney U tests (independent samples) were performed to determine whether the distributions of the six bone-related parameters showed significant differences between sexes and site locations. Study sites were categorized as either anterior (incisors and canines) or posterior (premolars and molars). The possible associations among variables (bone volume fraction [BV/TV], age, and five bone-related parameters) were examined using the Spearman rank correlation test. Results: The mean BV/TV values showed no significant difference between the maxillary anterior (46.93 ± 26.2) and posterior (51.90 ± 28.42) locations. Statistically significant positive correlations were identified between BV/TV and trabecular thickness (Tb.Th) (r = 0.6, P .001) and between BV/TV and trabecular number (Tb.N) (r = 0.49, P = .006). Statistically significant negative correlations were found between BV/TV and trabecular spacing (Tb.Sp) (r = -0.65, P .001), between BV/TV and trabecular pattern factor (Tb.Pf) (r = -0.7, P .001), and between BV/TV and the structural model index (SMI) (r = -0.68, P .001). However, no correlations between BV/TV and age or sex were found. Conclusion: Bone density was independent of the anatomical location, assessed by micro-CT in the pristine nonatrophic maxillary bone. Studies with a larger sample size and different population should be conducted to validate the findings of the current project. Keywords: alveolar ridge augmentation, bone, dental implant, grafting, maxillary ridge augmentation

Although some risk factors of peri-implant disease are well defined, the lack of efficient and predictable approaches to treat peri-implantitis has created difficulty in the management of those complications. The aim of this review was to evaluate the reliability of the diagnosis methods and to provide a set of guidelines to treat peri-implant diseases. A search of PubMed and a hand search of articles related to peri-implant diseases were conducted up to August 2013. A summary of the current methods for the diagnosis of peri-implantitis, its potential risk factors, and a flow chart to guide the clinical management of these conditions are presented.

Purpose: The aim of this study was to conduct a systematic review and meta-analysis to evaluate the influence of cantilevers upon implant-supported fixed partial dentures on marginal bone loss (MBL) and prosthetic-related complications. Materials and Methods: An electronic literature search was conducted in the PubMed database by two reviewers (LTM and AM) for articles written in English from June 2003 to January 2013 that were prospective human clinical trials with the clear purpose of appraising the effect of implant-supported fixed partial prostheses on peri-implant bone level and prosthetic complications. Data from the selected studies were extracted to carry out the statistical analysis. Results: Following the method described earlier, from initial research of 643 studies, 4 human clinical studies met the inclusion criteria and provided enough data to include them in the present meta-analysis. For the overall data, the pooled weighted mean (WM) of the MBL was 0.72 mm (range, 0.49 to 1.10 mm), with a 95% confidence interval (CI) of 0.36 to 1.08 mm. For the chi-square test, P = .60, representing a low heterogeneity among studies. MBL around implant-supported restorations with and without cantilevers was not found to be significant between both groups. The weighted mean difference (WMD) was 0.10 mm (favoring the noncantilever group), with a 95% CI = −0.18 to 0.39 mm (P = .47). For the chi-square test, P = .97, also indicating a low degree of heterogeneity between the studies. Conclusion: The dearth of scientific evidence in this matter does not permit clear conclusions to be drawn. However, within the limitations, marginal bone loss does not seem to be influenced by the presence of cantilever extensions. Moreover, minor technical complications were found when a cantilever was present when compared to the control groups. Keywords: cantilever, dental implant, endosseous implant, fixed prosthesis, implant-supported prosthesis, partial fixed prosthesis

Purpose: The aim of this study was to test the sensitivity of the resonance frequency analysis for detecting early implant failure. Materials and Methods: In all, 3,786 implants placed from June 2007 to January 2013 were retrospectively evaluated. A total of 20 implants (in 20 patients) placed in pristine bone were found to have failed before loading. The implant stability quotient (ISQ) values were extracted from these 20 implants at baseline (immediate) and 4 months after placement (delayed). Simple linear regression, logistic regression, and two-way contingency tables were used to test for the relationships between ISQ values and early implant failure. Results: Immediate ISQ values were significantly related to failure (odds ratio [OR] = 4.27). Furthermore, the results of the second regression showed a significant relationship between ISQ at delayed measurement and implant failure (OR = 9.20). For immediate ISQ, it seems that the 73.7% correct classifications were obtained at the cost of an incorrect classification of 55% of the implant failures. However, for the delayed ISQ, 86.2% correct classifications were obtained at the cost of assuming that all implants will survive. Conclusion: The present study showed that ISQ values are not reliable in predicting early implant failure. In addition, the real cutoff ISQ value to differentiate between success and early implant failure remains to be determined. Keywords: early failure, implant failure, implant stability, ISQ, primary stability, resonance frequency analysis

Purpose: The aim of this cone beam computed tomography (CBCT) study was to investigate the incidence of fenestration and associated risk factors with virtual placement of an implant in the maxillary incisor region. Materials and Methods: Edentulous ridges missing a maxillary central or lateral incisor and amenable for single implant placement were included. Root-form implants (4 × 12 mm and 3.5 × 12 mm for the central and lateral incisors, respectively) were placed virtually in the edentulous space following the axis of the ipsilateral crown. Buccolingually, the implants were placed in the ideal prosthetic cingulum position. The angles of the ridge (RA) and implants (IA) in relation to the hard palate and the incidence of fenestration were recorded. Results: A total of 48 CBCT scans were analyzed. The mean RA and IA were 124.32 degrees and 110.91 degrees, respectively. Nine cases resulted in fenestration, equivalent to 18.75% of the total cases. The discrepancy between the RA and IA was statistically significantly larger in the fenestration sites (19.93 degrees) than in the nonfenestration sites (13.05 degrees). The concavity depth of the alveolar ridge was statistically significantly higher in the fenestration sites (4.79 mm) than in the nonfenestration sites (3.40 mm). Conclusion: Within the limitations of this study, it can be concluded that the occurrence of fenestration is common (approximately 20%) if an implant is placed in the cingulum position with the axis following that of its restoration. Keywords: computed tomography, computer-guided surgery, cone beam virtual implant placement, dental implants, fenestration, maxilla

The primary purpose of this clinical study was to compare architectural metric parameters using microcomputed tomography (micro-CT) between sites grafted with blocks harvested from the mandibular ramus and calvarium for horizontal bone augmentation in the maxilla. The second aim was to compare the primary stability of implants placed in both types of block grafts. Ten consecutive healthy partially edentulous patients requiring extensive horizontal bone reconstruction in the maxilla were included. A total of 14 block grafts (7 each from the mandibular ramus and calvarium) were studied. After 4 to 6 months of healing, 41 implants were placed: 24 implants (58.5%) in calvarial (group 1) and 17 (41.5 %) in ramus grafts (group 2). A resonance frequency analysis (RFA) was performed to test implant stability. Furthermore, two biopsy specimens were randomly selected for histomorphometric analysis. Micro-CT analyses showed no significant difference in the morphometric parametric values analyzed between groups. Furthermore, RFA also showed no difference between groups. However, slightly higher RFA values were noted for implants placed in ramus grafts. Bone quality, as assessed by micro-CT and histomorphometric analyses, was similar in both ramus and calvarial block grafts. In addition, there was no difference in primary implant stability between groups.

Purpose: The primary aim of this systematic review was to compare the amount of marginal bone loss around tilted and straight implants. As the secondary aim, the incidence of biomechanic complications was compared. Materials and Methods: An electronic literature search from five databases, for the years 2000 to 2011, and a hand search in implant-related journals were conducted. Clinical human studies in the English language that had reported marginal bone loss in tilted and straight implants at 12-months followup or longer were included. Mean marginal bone loss and the number of implants that were available for analysis were extracted from original articles for meta-analyses. Results: Eight (six prospective and two retrospective) studies were included. One-year data were available in seven articles, which included 1,015 (451 tilted) implants. Three articles provided 3- to 5-year data from 302 (164 tilted) implants. No significant difference in weighted mean marginal bone loss was found between the tilted and straight implants in the short and medium terms. Three articles reported the incidence of biomechanic complications. There was not enough information to make a comparison. Conclusions: This meta-analysis failed to support the hypothesis that tilted implants that were splinted for the support of fixed prostheses had more marginal bone loss. Additionally, there was not enough evidence to claim a higher incidence of biomechanic complications in tilted implants. However, due to the nature of the study design of the included articles, caution should be exercised when interpreting the results of this review. Keywords: edentulous, immediate dental implant loading, marginal bone loss, nonaxial loading, splinting, tilted implant