Peri-implant Marginal Bone Loss Research Articles

Immediate Placement of Dental Implants in the Esthetic Zone: A Systematic Review and Pooled Analysis

Research interest on immediate placement of dental implants has shifted from implant survival toward optimal preservation of soft and hard tissues. The aim of this study is to systematically assess the condition of implant survival, peri-implant hard and soft tissue changes, esthetic outcome, and patient satisfaction of immediately placed single-tooth implants in the esthetic zone. MEDLINE, EMBASE, and CENTRAL databases were searched for publications up to June 2013. Studies reporting on implant survival, changes in hard and soft peri-implant tissues, esthetic outcome, and patient satisfaction were considered. A pooled analysis was performed to identify factors associated with survival and peri-implant tissue changes after immediate implant placement. Thirty-four studies were considered eligible. Immediate placement of single-tooth implants in the esthetic zone was accompanied by excellent 1-year implant survival (97.1%, 95% confidence interval [CI]: 0.958 to 0.980). Mean marginal peri-implant bone loss was 0.81 ± 0.48 mm, mean loss of interproximal peri-implant mucosa level was 0.38 ± 0.23 mm, and mean loss of peri-implant midfacial mucosa level was 0.54 ± 0.39 mm. Regression analysis revealed that delayed provisionalization (odds ratio [OR] 58.03, 95% CI: 8.05 to 418.41, P <0.000), use of a flap (OR 19.87, 95% CI: 10.21 to 38.66, P <0.000), and use of a connective tissue graft (OR 4.56, 95% CI: 1.72 to 12.08, P <0.002) were associated with marginal peri-implant bone-level change >0.50 mm. Because of underreporting, esthetic results and patient outcome did not allow for reliable analysis. Immediate placement with immediate provisionalization of dental implants in the esthetic zone results in excellent short-term treatment outcome in terms of implant survival and minimal change of peri-implant soft and hard tissue dimensions.

FRI0373 Clinical Outcome of Dental Implant Therapy in Patients with SjÖGren's Syndrome

BackgroundPatients with Sjögren's syndrome are subject to loss of teeth related to the high caries risk. Dental implant therapy is often considered as a proper possibility for prosthodontic rehabilitation of...

Implant treatment in atrophic posterior mandibles: vertical regeneration with block bone grafts versus implants with 5.5-mm intrabony length.

To retrospectively compare the outcomes of implants placed in posterior mandibles vertically regenerated with onlay autogenous block bone grafts and short dental implants. Consecutive patients with vertical bone atrophy in edentulous mandibular posterior regions (7 to 8 mm of bone above the inferior alveolar nerve) were treated with either implants placed in regenerated bone using autologous block bone grafts (group 1) or short implants (with 5.5-mm intrabony length) in native bone (group 2) between 2005 and 2010 and followed for 12 months after loading. The procedure used was the established treatment protocol for this type of patient at the Oral Surgery Unit (University of Valencia, Spain) at the time of surgery. All grafts were obtained using piezosurgery. The outcomes assessed were: complications related to the procedure, implant survival, implant success, and peri-implant marginal bone loss. Statistical analysis was done using the Fisher exact test and the Mann-Whitney test. Thirty-seven patients were included, 20 (45 implants) in group 1 and 17 (35 implants) in group 2. In group 1, 13 implants were less than 10 mm long (2 were 7 mm and 11 were 8.5 mm), and 32 were 10 mm or longer; the diameter was 3.6 mm in 6 implants, 4.2 mm in 31, and 5.5 mm in 8. In group 2 all implants were 7 mm long; the diameter measured 4.2 mm in 14 implants and 5.5 mm in 21 implants. Complications related to the block bone grafting procedure were temporary hypoesthesia in one patient, wound dehiscence with graft exposure in three patients, and exposure of the osteosynthesis screw without bone graft exposure in one patient. After 12 months, implant survival rates were 95.6% in group 1 and 97.1 % in group 2; success rates were 91.1% and 97.1%, respectively. The average marginal bone loss was 0.7 ± 1.1 mm in group 1 and 0.6 ± 0.3 mm in group 2. When residual bone height over the mandibular canal is between 7 and 8 mm, short implants (with 5.5-mm intrabony length) might be a preferable treatment option over vertical augmentation, reducing chair time, expense, and morbidity.

The effects of off-axial loading on periimplant marginal bone loss in a single implant

A discrepancy between crown width and implant width may contribute to potential bending overload. The purpose of this study was to evaluate the influence of the crown width-fixture width ratio on crestal bone loss around single dental implants placed in the first molar area. Seventy-six participants (37 men and 39 women; age range, 25-83 years; mean age [standard deviation], 56.3 ±10.6 years) were selected from individuals who were treated with single tooth implants between May 2004 and December 2009 at the Department of Periodontology, Gangnam Severance Dental Hospital. The marginal bone-level change and gingival parameters (modified plaque index and modified sulcus bleeding index) of the periimplant soft tissue were assessed 1 year after functional loading. The perpendicular distances from the vertical axis of each fixture to the most distal aspect of the crown and most mesial aspect of the crown were measured in the periapical radiographic view. No statistically significant relationship was found between crown width-fixture width ratio and the 1-year bone-level change (Pearson correlation, P=.06; Spearman rank test, P=.14). No statistically significant differences in marginal bone-level change were found between axial and nonaxial loading implants (2 independent samples t test; P=.19). The bone-level change for the surface adjacent and distant to the cantilever was not statistically significant (paired t test; P=.10). From this study, it may be concluded that off-axial loading that results from a high crown width-fixture width ratio does not increase the risk for periimplant marginal bone loss after 1-year functional loading.

Prosthetic Abutment Height is a Key Factor in Peri-implant Marginal Bone Loss

In this study, we analyzed the influence of prosthetic abutment height on marginal bone loss (MBL) around implants in the posterior maxilla. In this retrospective cohort study, the radiographically determined MBL was related to the height of the abutments of internal conical connection implants at 6 and 18 months post-loading. Data were gathered on age, sex, bone substratum, smoking habit, history of periodontitis, and prosthetic features, among other variables. A linear mixed model was used for statistical analysis. The study included 131 patients receiving 315 implants. MBL rates at 6 and 18 months were mainly affected by the abutment height but were also significantly influenced by the bone substratum, periodontitis, and smoking habit. MBL rates were higher for prosthetic abutment < 2 mm vs. ≥ 2 mm, for periodontal vs. non-periodontal patients, for grafted vs. pristine bone, and for a heavier smoking habit. The abutment height is a key factor in MBL. MBL rates followed a non-linear trend, with a greater MBL rate during the first 6 months post-loading than during the next 12 months.

Maxillary sinus floor augmentation using the transalveolar technique with simultaneous placement of dental implants: a 5-year clinical retrospective study

To evaluate the clinical and radiographic outcomes of placing dental implants in the posterior maxilla using the transalveolar technique. Between January 2005 and December 2009, a total of 94 cases, 55 males and 39 females, aged (46.9 ± 11.8) years, were consecutively enrolled in this study with maxillary sinus floor augmentation using the transalveolar technique. Radiographic evaluations were conducted on panoramic and periapical radiographs at each recall. The follow-up clinical examination included cumulative survival rate(CSR) of implants, peri-implant marginal bone loss (MBL) and the height of sinus floor augmentation and the endo-sinus bone gain (ESBG). Sinus membrane perforation was found in 4 cases.Finally 126 implants (90 cases) were placed. The perforation rate of this surgical procedure was 3.08% (4/130).Four implants lost during the healing time, the early success of implants was 96.80% (121/125). During a mean follow-up time of (34.4 ± 20.4) months, all the implants were successfully in function, with the cumulative survival rate after function loading of 100.00%. The mean MBL was (0.75 ± 0.51) mm during the healing time, and (0.48 ± 0.41) mm during the follow-up period. The mean residual bone height (RBH) was (7.27 ± 1.30) mm at the position of implants placement, the length of implant protruding into the sinus was (2.77 ± 1.15) mm, and the height of sinus floor augmentation was (4.52 ± 1.39) mm. At the loading time, the mean endo-sinus bone gain was (3.81 ± 1.60) mm. After the follow-up time of 34 months, the newly formed bone on the maxillary sinus floor underwent further remodeling with a median bone reduction value of 0.37 (0.10, 0.88) mm. Maxillary sinus floor augmentation using the transalveolar technique is a predictable treatment modality. The augmentation of the maxillary sinus floor using the transalveolar technique could lead to bone formation under the sinus. The newly formed bone showed slight absorbtion in the long term follow-up.

Impact of platform switching on marginal peri‐implant bone‐level changes. A systematic review and meta‐analysis

ObjectiveTo address the focused question, is there an impact of platform switching (PS) on marginal bone level (MBL) changes around endosseous implants compared to implants with platform matching (PM) implant-abutment configurations?Material and methodsA systematic literature search was conducted using electronic databases PubMed, Web of Science, Journals@Ovid Full Text and Embase, manual search for human randomized clinical trials (RCTs) and prospective clinical controlled cohort studies (PCCS) reporting on MBL changes at implants with PS-, compared with PM-implant-abutment connections, published between 2005 and June 2013.ResultsTwenty-two publications were eligible for the systematic review. The qualitative analysis of 15 RCTs and seven PCCS revealed more studies (13 RCTs and three PCCS) showing a significantly less mean marginal bone loss around implants with PS- compared to PM-implant-abutment connections, indicating a clear tendency favoring the PS technique. A meta-analysis including 13 RCTs revealed a significantly less mean MBL change (0.49 mm [CI95% 0.38; 0.60]) at PS implants, compared with PM implants (1.01 mm [CI95% 0.62; 1.40] (P < 0.0001).ConclusionsThe meta-analysis revealed a significantly less mean MBL change at implants with a PS compared to PM-implant-abutment configuration. Studies included herein showed an unclear as well as high risk of bias mostly, and relatively short follow-up periods. The qualitative analysis revealed a tendency favoring the PS technique to prevent or minimize peri-implant marginal bone loss compared with PM technique. Due to heterogeneity of the included studies, their results require cautious interpretation.

Peri-implant Bone Loss Around Single and Multiple Prostheses: Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to assess and compare the marginal bone loss around implants supporting single fixed prostheses and multiple-unit screw-retained prostheses. The literature was searched manually and electronically to identify studies in which the marginal peri-implant bone loss around single-implant prostheses and screw-retained multiple-implant prostheses was evaluated radiographically. Two reviewers independently selected the literature and extracted the data. The random-effects method was used to obtain estimates of marginal peri-implant bone loss (means and 95% confidence intervals [CIs]). Of the 2,107 studies identified by a preliminary search, 17 fulfilled the inclusion criteria; 7 were related to single-implant prostheses and 10 to multiple-implant screw-retained fixed prostheses. The mean marginal peri-implant bone loss was 0.9 mm (95% CI, 0.49 to 1.32 mm) for multiple-implant screw-retained prostheses and 0.58 mm (95% CI, 0.37 to 0.80 mm) for single-implant prostheses. This indirect comparison provided no evidence to support the assertion that there are differences in marginal peri-implant bone loss between single implant prostheses and multiple screw-retained prostheses.

Maxillary overdentures supported by four splinted direct metal laser sintering implants: a 3-year prospective clinical study.

Purpose. Nowadays, the advancements in direct metal laser sintering (DMLS) technology allow the fabrication of titanium dental implants. The aim of this study was to evaluate implant survival, complications, and peri-implant marginal bone loss of DMLS implants used to support bar-retained maxillary overdentures. Materials and Methods. Over a 2-year period, 120 implants were placed in the maxilla of 30 patients (18 males, 12 females) to support bar-retained maxillary overdentures (ODs). Each OD was supported by 4 implants splinted by a rigid cobalt-chrome bar. At each annual follow-up session, clinical and radiographic parameters were assessed. The outcome measures were implant failure, biological and prosthetic complications, and peri-implant marginal bone loss (distance between the implant shoulder and the first visible bone-to-implant contact, DIB). Results. The 3-year implant survival rate was 97.4% (implant-based) and 92.9% (patient-based). Three implants failed. The incidence of biological complication was 3.5% (implant-based) and 7.1% (patient-based). The incidence of prosthetic complication was 17.8% (patient-based). No detrimental effects on marginal bone level were evidenced. Conclusions. The use of 4 DMLS titanium implants to support bar-retained maxillary ODs seems to represent a safe and successful procedure. Long-term clinical studies on a larger sample of patients are needed to confirm these results.

Clinical Outcome of Narrow-Diameter (3.3-mm) Locking-Taper Implants: A Prospective Study with 1 to 10 Years of Follow-up

To evaluate the outcome of narrow-diameter (3.3-mm) locking-taper implants used in the rehabilitation of partially and fully edentulous patients over a 10-year period. Between January 2002 and December 2011, all patients referred to a private dental clinic for treatment with narrow-diameter implants were enrolled in this study. At each annual follow-up session, clinical and radiographic parameters were assessed; the outcome measurements were implant failure, peri-implant marginal bone loss (distance between the implant shoulder and the first visible bone-to-implant contact [DIB]), and biologic and technical complications. The cumulative survival rate (CSR) was assessed using the Kaplan-Meier survival estimator; Tarone-Ware and chi-square analyses were used to evaluate correlations between the study variables. The statistical analysis was performed at the patient- and implant-level. A total of 324 narrow-diameter implants were placed in 279 patients (159 men, 120 women; age: 25 to 73 years). Four implants failed, for an overall CSR of 98.5% (patient-based) and 98.7% (implant-based) at the 10-year follow-up. The survival rate did not differ significantly with respect to patients' sex, age, smoking or parafunctional habits, bone type, prosthetic restoration, or implant location, position, or length. Among the surviving implants, a mean DIB of 0.31 ± 0.23 mm, 0.45 ± 0.27 mm, and 0.69 ± 0.28 mm was observed at the 1-, 5-, and 10-year follow-up examinations, respectively. A few biologic (1.2%) and technical complications (7.5%) were reported. Within the limitations of this study, it can be concluded that narrow-diameter locking-taper implants represent a good treatment option for the prosthetic rehabilitation of partially and totally edentulous patients.

Single-blind randomized clinical trial to evaluate clinical and radiological outcomes after one year of immediate versus delayed implant placement supporting full-arch prostheses

Purpose: To evaluate and compare peri-implant health, marginal bone loss and success of immediate and delayed implant placement for rehabilitation with full-arch fixed prostheses. Material and Methods: The present study was a prospective, randomized, single-blind, clinical preliminary trial. Patients were randomized into two treatment groups. In Group A implants were placed immediately post-extraction and in Group B six months after extraction. The following control time-points were established: one week, six months and twelve months after loading. Measurements were taken of peri-implant crevicular fluid volume, plaque index, gingival retraction, keratinized mucosa, probing depth, modified gingival index and presence of mucositis. Implant success rates were evaluated for the two groups. The study sample included fifteen patients (nine women and six men) with a mean average age of 63.7 years. One hundred and forty-four implants were placed: 76 placed in healed sites and 68 placed immediately. Results: At the moment of prosthetic loading, keratinized mucosa width and probing depth were higher in immediate implants than delayed implants, with statistically significant differences. However, after six and twelve months, differences between groups had disappeared. Bone loss was 0.54 ± 0.39 mm for immediate implants and 0.66 ± 0.25 mm for delayed implants (p=0.201). No implants failed in either group. Conclusions: The present study with a short follow-up and a small sample yielded no statistically significant differences in implant success and peri-implant marginal bone loss between immediate and delayed implants with fixed full-arch prostheses. Peri-implant health showed no statistically significant differences for any of the studied parameters (crevicular fluid volume, plaque index, gingival retraction, keratinized mucosa, probing depth, modified gingival index and presence of mucositis) at the twelve-month follow-up. Key words:Immediate implants, delayed implants, peri-implant health, success rate.

Effect of Crown to Implant Ratio and Anatomical Crown Length on Clinical Conditions in a Single Implant: A Retrospective Cohort Study

The aim of this retrospective cohort study was to evaluate the long-term influence of the crown-to-implant (C/I) ratio and anatomical crown length on clinical conditions around Astra single dental implants placed in the premolar and molar regions. Seventy-six subjects were selected from patients who had been treated with single Astra implants for replacement of missing premolars and molars. The peri-implant marginal bone level change was assessed 1 year after functional loading and 6 years after functional loading. To predict the peri-implant marginal bone level change using clinical and radiographic data, a multiple linear regression model was applied. The Wilcoxon rank sum test was used to analyze difference median in technical complications. The C/I ratio and anatomical crown length were not associated with peri-implant marginal bone loss or changes in the bone level at 6 years (p = .48, p = .31). However, the modified plaque index, modified sulcus bleeding index, and smoking status influenced the peri-implant marginal bone loss (p < .05, r(2) = 0.54). In addition, the patient with technical complication group did show significantly increased anatomical crown length (p < .05) CONCLUSIONS: The higher C/I ratio and anatomical crown length did not increase the risk of peri-implant marginal bone loss during 6 years of functional loading. In addition, higher anatomical crown lengths are associated with higher technical complications.

The All-on-Four Implant Therapy Protocol in the Management of Edentulous Chinese Patients

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. 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.

Piezoelectric vs. conventional drilling in implant site preparation: pilot controlled randomized clinical trial with crossover design

To compare implant stability throughout osseointegration, peri-implant marginal bone loss, and success rates of implants placed with conventional and mixed drilling/piezoelectric osteotomy. A pilot randomized-controlled trial was performed on 15 patients. Each patient received two implants in the mandibular molar region. All sites were prepared with conventionally up to the 2.8 mm wide drill. Osteotomies were randomly finalized with a 3 mm diameter drill (control group) or with two consecutive ultrasonic tips (2.8 mm and 3 mm wide, respectively) (test group). Resonance frequency analysis measurements were taken at implant placement and after 1, 3, 8, and 12 weeks. Peri-implant marginal bone loss 12 months after loading was calculated using periapical radiographs. Wilcoxon test for related samples was used to study differences in implant stability and in peri-implant marginal bone loss between the two groups. Twenty-nine of 30 implants osseointegrated successfully (one failure in the control group). Stability was significantly higher in the test group at the 8th week assessment; differences were non-significant at all other time-points. Longitudinally, differences were observed between the patterns of implant stability changes: in the test group stability increased more progressively, while in the control group an abrupt change occurred between the 8th and 12th weeks assessments. No difference was found in peri-implant marginal bone loss between the groups. All 29 implants were functionally successful at the 15-month visit. Within the limit of this pilot study (small sample size, short follow-up), data suggested that implant stability might develop slightly faster when implant site osteotomy is performed with a mixed drilling/ultrasonic technique.

A systematic review on marginal bone loss around short dental implants (&lt;10 mm) for implant‐supported fixed prostheses

This systematic review aimed to evaluate the effect of implant length on peri-implant marginal bone loss (MBL) and its associated influencing factors. An electronic search of the PubMed and MEDLINE databases for relevant studies published in English from November 2006 to July 2012 was performed by one examiner (AM). Selected studies were randomized clinical trials, human experimental clinical trials or prospective studies (e.g., cohort as well as case series) with a clear aim of investigating marginal bone loss of short dental implants (<10 mm) supporting fixed prostheses. A random-effect meta-regression model was used to determine the relationship between the effect size mean MBL and the covariate "implant length." Additionally, a subgroup analysis, by means of a random-effect one-way ANOVA model, comparing mean MBL values at different levels of each factor ("type of connection" and "type of prostheses") was also performed. The meta-regression of mean MBL on the moderator "implant length" was found to be insignificant (P = 0.633). Therefore, it could not be concluded that implant length had an effect on peri-implant MBL. In addition, standardized differences in mean MBL on the subgroups short (<10 mm) and standard (≥ 10 mm) implants, as determined by the meta-analysis (random-effect model), were found to be statistically insignificant (P = 0.222). Within limitations of the present systematic review, it could be concluded that short dental implants (<10 mm) had similar peri-implant MBL as standard implants (≥ 10 mm) for implant-supported fixed prostheses.

패턴인식 알고리즘을 적용한 임플란트 주변골 흡수 분석

Purpose: The aim of this study is to analyze the series of panoramic radiograph of implant patients using the system to measure peri-implant crestal bone loss according to the elapsed time from fixture installation time to more than three years. Methods: Choose 10 patients having 45 implant fixtures installed, which have series of panoramic radiograph in the period to be analyzed by the system. Then, calculated the crestal bone depth and statistics and selected the implant in concerned by clicking the implant of image shown on the monitor by the implemented pattern recognition system. Then, the system recognized the x, y coordination of the implant and peri-implant alveolar crest, and calculated the distance between the approximated line of implant fixture and alveolar crest. By applying pattern recognition to periodic panoramic radiographs, we attained the results and made a comparison with the results of preceded articles concerning peri-implant marginal bone loss. Analyzing peri-implant crestal bone loss in a regression analysis periodic filmed panoramic radiograph, logarithmic approximation had highest <TEX>$R^2$</TEX> value, and the equation is as shown below. <TEX>$y=0.245Logx{\pm}0.42$</TEX>, <TEX>$R^2=0.53$</TEX>, unit: month (x), mm (y) Results: Panoramic radiograph is a more wide-scoped view compared with the periapical radiograph in the same resolution. Therefore, there was not enough information in the radiograph in local area. Anterior portion of many radiographs was out of the focal trough and blurred precluding the accurate recognition by the system, and many implants were overlapped with the adjacent structures, in which the alveolar crest was impossible to find. Conclusion: Considering the earlier objective and error, we expect better results from an analysis of periapical radiograph than panoramic radiograph. Implementing additional function, we expect high extensibility of pattern recognition system as a diagnostic tool to evaluate implant-bone integration, calculate length from fixture to inferior alveolar nerve, and from fixture to base of the maxillary sinus.

High Bone-Implant Contact Achieved by Photofunctionalization to Reduce Periimplant Stress

A recent study demonstrated that UV treatment of titanium implants (photofunctionalization) enabled a higher level of osseointegration by establishing a 98.2% bone-implant contact (BIC) as opposed to a 53.0% BIC around untreated implants. This study examined whether, and how, the BIC increase affects the periimplant mechanical stress. Three-dimensional finite element analysis was performed on implants of different degrees of BIC (53.0% and 98.2%) based on the report of photofunctionalization. The different lengths of implants (7, 10, and 13 mm) were also tested. Increasing the implant length from 7 to 13 mm diminished the periimplant stress level by only 15% under vertical load, whereas increasing BIC from 53.0% to 98.2% diminished it by 50%. Consequently, stress around 7-mm implants with 98.2% BIC was even lower than that around 13-mm implants with 53.0% BIC. High-stress areas, which were observed around implants in all lengths with 53.0% BIC, disappeared on implants with 98.2% BIC even on 7-mm implants. Similar results were obtained under oblique load. This study demonstrated that a BIC increase from 53.0% to 98.2%, which can be achieved by photofunctionalization, improves distribution and diffusion of periimplant stress more effectively than using longer implants, providing a potential novel strategy to counteract stress-induced periimplant marginal bone loss.

Peri‐implant bone loss in cement‐ and screw‐retained prostheses: Systematic review and meta‐analysis

The aim of this systematic review and meta-analysis was to assess and compare peri-implant marginal bone loss in cement- and screw-retained prostheses. Electronic database and manual searches were undertaken to identify trials, prospective or retrospective studies reporting on radiographic marginal bone loss around dental implants restored with cement- and/or screw-retained prostheses. Two reviewers independently conducted the article selection and data extraction. Random-effects models were used to obtain estimates of peri-implant marginal bone loss [mean, 95% confidence intervals (CI)]. Of the 1217 identified studies, nine finally met the inclusion criteria. Only two studies included both cement- and screw-retained prostheses, three assessed only screw-retained prostheses, and four evaluated only cement-retained prostheses. Pooled mean marginal bone loss was 0.53mm (CI 95%, 0.31-0.76mm) for cement-retained prostheses and 0.89mm (CI 95%, 0.45-1.33mm) for screw-retained prostheses. There is no evidence to support differences in the marginal bone loss through indirect comparison between cement and screw-retained restorations.

Localized Lateral Alveolar Ridge Augmentation with Block Bone Grafts: Simultaneous Versus Delayed Implant Placement: A Clinical and Radiographic Retrospective Study

To retrospectively evaluate the 1-year outcome of implant therapy involving localized lateral alveolar ridge augmentation with block bone grafts, and to compare outcomes of implants inserted simultaneously with grafting or after a healing period. Consecutively treated patients undergoing alveolar ridge augmentation with autogenous intraoral block grafts before or simultaneous with implant placement between 2005 and 2010 in the Oral Surgery Unit of the University of Valencia were included. The selection of procedure (simultaneous vs delayed implant placement, donor site) was based upon the criterion of the surgeon and thorough evaluation of each patient. All grafts were obtained with piezosurgery. Complications related to augmentation, implant survival, implant success, and peri-implant marginal bone loss were assessed. Forty-two patients were included; 45 sites were augmented and 71 implants were inserted (33 delayed and 38 simultaneously). Complications (temporary paresthesia, wound dehiscence with bone graft exposure, and exposure of osteosynthesis screw) occurred after bone harvesting in nine patients; four were in the simultaneous group and five were in the delayed group. Six grafts were not successful; four were lost and two provided insufficient bone (after resorption) for ideal implant placement. The implant survival rate was 98.5% (100% for simultaneous and 96.9% for delayed implants) and the implant success rate was 92.9% (89.5% for simultaneous and 96.9% for delayed implants). Average marginal bone loss 1 year after loading was significantly higher for simultaneously placed implants (0.69 ± 0.67 mm) than for delayed implants (0.20 ± 0.50 mm). In lateral bone atrophy, block bone grafts provided sufficient bone for implant therapy, with few complications. Both simultaneous and delayed implant placement yielded high implant survival and success rates. Average marginal bone loss was significantly higher around simultaneously inserted implants.

Immediate Versus Conventional Loading for the Maxilla with Implants Placed into Fresh and Healed Extraction Sites to Support a Full-Arch Fixed Prosthesis: Nonrandomized Controlled Clinical Study

To compare immediate and conventional loading of fixed full-arch maxillary prostheses supported by implants placed in healed and fresh postextraction sites. This prospective, controlled, nonrandomized 12-month study included 30 consecutive patients requiring fixed full-arch maxillary prostheses supported by implants placed in healed and fresh extraction sites. Fifteen patients were treated with conventional loading (control group), and 15 were treated with immediate loading (test group). Each patient received six to eight implants; implants with insertion torque < 35 Ncm were conventionally loaded and excluded from the analysis. Implant success, biologic and prosthetic complications, success of the immediately loaded provisional prostheses, and marginal bone loss were assessed and analyzed statistically. One test group patient failed to attend recall visits and was excluded from the study, and 16 implants did not achieve insertion torque of 35 Ncm and were excluded from analyses. The final sample included 29 patients and 193 implants (94 test implants, 99 control implants). Implant success rates were 96.8% (test) and 99.0% (control). In the test group, the most common complications were screw loosening and tooth fractures; in the control group, dentures caused discomfort and soft tissue irritation. The success rate of the immediately loaded prostheses was 100%. Average bone loss was 0.61 ± 0.21 mm for test implants and 0.53 ± 0.18 mm for control implants. Differences between loading protocols were not statistically significant. No significant differences in implant success and peri-implant marginal bone loss were seen in the current 12-month comparison of immediate and conventional loading of maxillary fixed full-arch prostheses. Biologic and prosthetic complications were rare with both loading protocols, and all immediately loaded provisional fixed prostheses performed successfully.