Difference In Marginal Bone Level Research Articles

Differences in Titanium, Titanium-Zirconium, Zirconia Implants Treatment Outcomes: a Systematic Literature Review and Meta-Analysis.

The objective of this systematic review is to test the hypothesis that treatment with titanium, titanium-zirconium and zirconia dental implants has different clinical outcomes in survival rate, marginal bone loss, bleeding on probing, plaque control record, and probing depth. A systematic electronic search through the PubMed (MEDLINE) and Cochrane Library databases was performed to identify studies published between January 1, 2013 and January 1, 2023 containing a minimum of 10 patients per study comparing titanium (Ti), titanium-zirconium (Ti-Zr), and zirconia (Zr) dental implants. Ti, Ti-Zr, and Zr dental implant clinical outcomes were determined by evaluating survival rate, marginal bone level, bleeding on probing, probing depth, plaque control record. Quality and risk-of-bias assessment were evaluated by Cochrane risk of bias tool. A total of 1361 articles were screened, with 10 meeting the inclusion criteria and being utilized for this systematic review and meta-analysis. A total of 301 patients with 637 implants (304 Ti, 134 Ti-Zr, and 199 Zr) were evaluated, showing a survival rate of 97.7% for Ti, 98.6% for Ti-Zr, and 93.8% for Zr implants respectively. In a meta-analysis, no difference in marginal bone level was found between Ti, Ti-Zr, and Zr implants (P = 0.84). Dental implant survival rate was lower in zirconia group. Assessment of marginal bone loss and bleeding on probing showed better results with titanium-zirconium dental implants. Plaque control result was similar in all groups. Due to limited sample size assessed it was not possible to obtain conclusion on probing depth parameter.

Clinical outcomes of full-arch immediate fixed prostheses supported by two axial and two tilted implants: A retrospective cohort study with 12-15 years of follow-up.

To retrospectively assess clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by axial and tilted implants up to 15 years of function. Patients with one completely edentulous arch received an immediate full-arch fixed prosthesis supported by two anterior axial and two posterior tilted implants. Definitive prosthesis consisting of a CAD-CAM titanium framework and acrylic teeth was delivered 6months later. Patients were regularly followed to assess clinical parameters and marginal bone level (MBL) change. Multilevel regression analysis was performed to investigate factors affecting implant failure and MBL. Six hundred ninety-two implants were placed in 72 maxillae and 101 mandibles. Seven maxillary implants (5 axial and 2 tilted) in 6 patients and 12 mandibular implants (6 axial and 6 tilted) in 5 patients failed. 15-year cumulative implant survival was 97.51% and 96.91% in maxilla and mandible, respectively (p=.64). After 10 years, the difference in MBL between axial and tilted implants was not significant in the maxilla (p=.47, 65 patients), while it was in the mandible (p < .001, 80 patients). Significant higher bone loss was reported in the mandible at both 5- and 10-year follow-up (p < .001 and p=.004, respectively). Mixed-effect multilevel linear regression evidenced a correlation between arch and bone loss at 5- and 10-year follow-up, while no correlation was found with age, gender, smoking, diabetes, and history of periodontal disease. This long-term study suggests that the present technique can be considered a viable treatment modality for the immediate rehabilitation of both maxilla and mandible.

Clinical and Radiologic Evaluation of a Fully Tapered Implant with Immediate Placement in the Esthetic Zone: A Prospective Case Series Study.

A fully tapered implant was recently introduced to increase primary stability and to be used in challenging situations. Twenty single implants were inserted in maxillary postextraction sockets, from premolar to premolar, and immediately restored. Marginal bone level (MBL) and probing depth (PD) were evaluated over a 12-month follow-up period. All implants osseointegrated, achieving a success rate of 100%. The difference in MBL between implant placement and 1 year later was 0.20 ± 0.04 mm, while PD was 2.82 ± 0.51 mm at 1 year. The data reported here support the use of a fully tapered implant for immediate placement and immediate provisionalization for single-tooth replacements in the esthetic area.

Multivariate analysis of the influence of prosthodontic factors on peri-implant bleeding index and marginal bone level in a molar site: A cross-sectional study.

Peri-implant tissue condition can result from prosthodontic, surgical and bacteriological factors. This study investigated the effects of prosthodontic factors on peri-implant tissue. Subjects were 140 patients with 310 implants from Osaka University Dental Hospital. Prosthodontic factors examined were the connection type, the suprastructure retention type, the material of the abutment and the mesiodistal and buccolingual prosthetic form of the superstructure as emergence angle. The objective variables were the modified bleeding index (mBI) and marginal bone level (MBL). Statistical analysis was used as a generalized estimation equation. The taper joint had a significantly smaller MBL than the butt joint (P < .001). There was no significant difference in mBI and MBL between cement and screw retaining. Zirconium and titanium resulted in a significantly smaller mBI than gold alloy (zirconium/gold alloy: P = .037, titanium / gold alloy: P = .021), but there was no significant difference in the MBL. Both mBI and MBL tended to be smaller when the emergence angle was around 20° to 40°, although this difference was not significant. As a result of multivariate analysis, our findings suggest that to reduce MBL from the perspective of prosthodontic factors it is preferable to use an implant with a taper joint connection positioned with an emergence angle of 20° to 40°.

Implant splinting in mandibular overdentures: a systematic review with meta-analysis of randomized clinical trials.

To evaluate the influence of implant splinting on peri-implant marginal bone level and implant failures in completely edentulous patients who have been rehabilitated with mandibular implant overdentures. A literature search of electronic databases (PubMed and Cochrane Central Register of Controlled Trials [CENTRAL]) was performed, with the last search conducted in July 2019. Randomized controlled trials with at least a 12-month follow-up period were selected. The review and meta-analysis were performed in accordance with PRISMA guidelines. Two comparisons were included in the meta-analysis: (1) Two-implant supported ball versus two-implant supported bar mandibular overdenture; (2): Two- versus four-implant supported bar mandibular overdenture. Six randomized controlled trials fulfilled the inclusion criteria and were included in a quality assessment and meta-analysis. Pooled data revealed a nonsignificant difference in marginal bone level (I2 = 0%; P = 1; mean difference = 0.00; 95% CI -0.37 to 0.37) and implant failures (P = .24; risk ratio = 6.07; 95% CI 0.30 to 121.33) when two-implant ball overdentures were compared to two-implant bar overdentures. Similarly, there was no significant difference in marginal bone level (I2 = 59%; P = .59; mean difference = -0.16; 95% CI -0.73 to 0.41) or implant failures (I2 = 0%; P = .36; risk ratio = 2.03; 95% CI 0.45 to 9.16) when two- versus four-implant bar overdentures were compared. Based on the findings of the meta-analysis, there is no influence of implant splinting on peri-implant marginal bone level and implant failures for completely edentulous patients rehabilitated with mandibular implant overdentures. However, this result should be interpreted with caution due to the limited number of analyzed studies, most of them considered at unclear risk of bias. Well-designed randomized controlled trials with follow-up periods of at least 5 years are highly recommended to establish evidence with regard to the influence of implant splinting on mandibular overdentures.

Sandblasting reduces dental implant failure rate but not marginal bone level loss: A systematic review and meta-analysis.

IntroductionSandblasting is one of the oldest implant surface modifications to enhance osseointegration. Regarding its superiority over machined surface controversies still exist. Our objective was to compare implant failures (IF) and marginal bone level (MBL) changes between sandblasted and machined dental implants by a meta-analysis utilizing the available data. The PROSPERO registration number of the meta-analysis is CRD42018084190.MethodsThe systematic search was performed in Cochrane, Embase and Pubmed. Inclusion criteria included participants with neither systemic diseases, nor excessive alcohol consumption, nor heavy smoking. We calculated pooled Risk Ratio (RRs) with confidence intervals of 95% (CIs) for dichotomous outcomes (implant failure) and weighted mean difference (WMD) CIs of 95% for continuous outcomes (marginal bone level change). We applied the random effect model with DerSimonian-Laird estimation. I2 and chi2 tests were used to quantify statistical heterogeneity and gain probability-values, respectively.ResultsLiterature search revealed 130 records without duplicates. Out of these, seven studies met the inclusion criteria and all were included in data synthesis, involving 362 sand-blasted and 360 machined implants. The results indicate that there is an 80% (RR = 0.2 95% CI:0.06–0.67; I2 = 0.0% p = 0.986) lower among sandblasted compared to machined implants after one year of use and 74% (RR = 0.26 95% CI:0.09–0.74; I2 = 0.0% p = 0.968) five years of use, respectively. In contrast, there is no significant difference in MBL (WMD:-0.10mm, 95% CI:-0.20, 0.01; p>0.05; I2 = 0.0%, p = 0.560 and WMD:-0.01mm, 95% CI:-0.12, 0.09; p>0.05; I2 = 26.2%, p = 0.258) between the two implant surfaces after one and five years of use.ConclusionsThis meta-analysis reveals that sandblasting is superior over machined surface in implant failure but not in marginal bone level in healthy subjects. It also points out the need for further randomized clinical trials with large sample size for objective determination of the clinical benefits of certain implant surface modifications.

Short Implants and Conventional Implants in The Residual Maxillary Alveolar Ridge: A 36-Month Follow-Up Observation.

BackgroundShort dental implants are considered an alternative method of treatment to the maxillary sinus elevation and bone augmentation procedure at the sites of a reduced alveolar ridge height.The aim of the study was to determine the most effective therapeutic approach for a single tooth replacement in a reduced maxillary alveolar crest.Material/MethodsWe enrolled 30 partially edentulous patients having a residual crestal height of 6 mm and a minimal width of the alveolar ridge of 6–7 mm: 15 patients received regular dental implants (OsseoSpeed™ L11 Ø4 mm and L13 Ø4 mm) and the implantation was preceded by the sinus lift procedure from a lateral window approach with the application of a xenogeneic bone graft, whereas the remaining 15 patients received short implants (OsseoSpeed™ L6 mm Ø4 mm) without the sinus lift and augmentation procedure.All implants were loaded with single non-splinted crowns. Radiological examination (CBCT, RVG) was performed before the surgery and after 36 months. Primary and secondary stabilization with Osstell ISQ® and Periotest® were assessed.ResultsGood results in primary and secondary stability were achieved in both systems. The marginal bone level (MBL) loss was low (0.22±0.46 mm and 0.34±0.24 mm, for short and conventional implants, respectively). No significant difference in MBL between groups was found.ConclusionsShort implants can be successfully used to support single crowns in the lateral part of the maxilla.

The Efficacy of an Anatase-Coated Collar Surface in Inhibiting the Bacterial Colonization of Oral Implants: A Pilot Prospective Study in Humans.

The primary prevention of peri-implantitis onset is a key factor in long-term implant success, and the evaluation of the antibacterial efficacy of different implant surfaces is fundamental in this way. The aim of this study was to assess if implants with collars coated with anatase were less subjected to bacterial colonization than implants with noncoated collars, and to investigate how implant bacterial colonization varies over time. Eighteen patients in need of implant-supported rehabilitation were selected to have two adjacent implants placed, one with an anatase-coated collar and one with the collar uncoated. Biofilm samples were collected at four sites around each implant at four different time points. Samples were analyzed through polymerase chain reaction (PCR) to detect and calculate the colonization rate of Aggregactibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Prevotella intermedia. Due to one patient dropout and two nonosseointegrated implants, 32 out of 36 placed implants were followed up for 12 months, and 128 samples for each time point were collected: in total, 512 biofilm samples were analyzed. The type and rate of bacterial colonization were not significantly different between the two groups at all the intervals. However, the anatase-coated collar showed no proliferation of T forsythia. A significant difference in marginal bone level could be observed at the 12-month follow-up only. No significant difference in the other clinical and radiographic indexes was observed. In this study, anatase-coated collar implants did not seem to provide significantly different microbiologic outcomes than uncoated collar implants. However, the absence of colonization of the species T forsythia and the slightly smaller peri-implant bone loss at the 12-month follow-up suggest that further investigations on anatase coating are needed. Nevertheless, data on bacterial colonization and crestal bone levels need further investigations to draw meaningful conclusions, due to the statistical power of this pilot study.

Immediate Single-Tooth Implant Placement in Bony Defects in the Esthetic Zone: A 1-Year Randomized Controlled Trial.

This study aims to assess, with regard to marginal bone level (MBL), whether the outcome of immediate implant placement in bony defects in the esthetic zone was non-inferior to delayed implant placement after 1 year. Forty patients with a failing tooth in the esthetic zone and a labial bony defect of ≥5 mm after removal of a tooth were randomly assigned for immediate (n = 20) or delayed (n = 20) implant placement. Second-stage surgery and provisionalization occurred after 3 months of healing. Follow-up was at 1 month and 1 year after definitive crown placement. The study was powered to detect a difference in MBL of >0.9 mm. Buccal bone thickness, soft tissue peri-implant parameters, esthetic indices, and patient satisfaction were also assessed. One year after definitive crown placement, MBL loss was 0.56 ± 0.39 mm mesially and 0.74 ± 0.51 mm distally for the immediate placement group and 0.51 ± 0.43 mesially and 0.54 ± 0.45 distally mm for the delayed placement group, respectively (not significant). Regarding differences in means, non-inferiority was observed after 1 year (difference in mean for immediate versus delayed: mesially 0.04 mm [95% confidence interval (CI) = -0.22 to 0.30 mm, P = 0.40]; distally 0.21 mm [95% CI = -0.10 to 0.51 mm, P = 0.58]). No significant differences in the other outcome variables were observed. Immediate implant placement with delayed provisionalization was non-inferior to delayed implant placement with delayed provisionalization in labial bony defects of ≥5 mm regarding change in MBL. Although not powered for other outcome variables, no clinically relevant differences were observed in these variables.

A Retrospective 2-Year Clinical Study of Immediate Prosthetic Rehabilitation of Edentulous Jaws with Four Implants and Prefabricated Bars.

The purpose of this retrospective investigation was to evaluate the use of a prefabricated bar system for immediately loaded implants placed and restored according to the All-on-Four concept with up to 24-month follow-up. A total of 51 patients (31 males and 20 females; mean age 63.4 years) presented with edentulous or partially edentulous jaws with severe atrophy of the posterior regions. All patients were treated with full-arch fixed prostheses (28 maxillary, 34 mandibular) each supported by four implants (two vertical, two distally tilted). The implants were immediately loaded with screw-retained full-arch restorations. Each prosthesis was supported by a prefabricated metal bar combined with high-density acrylic resin. Follow-up visits were scheduled at 6, 12, and 24 months after initial prosthetic loading. Intraoral radiographs were obtained immediately after surgery and at each follow-up visit by using a custom radiograph holder and parallel technique. Marginal bone levels were assessed using digital image analysis. Implant and prosthetic survival and success rates were evaluated. Patient satisfaction was further assessed using a 100-mm visual analog scale (VAS). Data were compared by means of the Mantel-Haenszel test. No drop-outs occurred. The overall implant survival rates were 100% and 98.38% for the vertical and tilted implants respectively. Two of the 62 definitive fixed prostheses were lost during the observation period due to implant failure. Since restoration replacement due to implant failure was not judged a prosthodontic failure according to the survival criteria provided in this study, the overall prosthetic survival rate was 100%. No statistically significant differences in marginal bone levels between vertical and tilted implants were detected at 24-month follow-up evaluation in either jaw. All participants were functionally and esthetically satisfied with their definitive restorations after 2 years functioning, as confirmed by the average VAS scores (masticatory function: 99.7; phonetic function: 99.5, esthetics: 99.2). The preliminary 24-month results indicate that immediate loading of vertical and tilted implants using the evaluated prefabricated bar system may be a viable solution for edentulous jaw rehabilitation; however, more long-term prospective clinical trials are needed to affirm the effectiveness of this surgical-prosthetic protocol.

Feasibility of immediate placement of single-tooth implants in the aesthetic zone: a1-year randomized controlled trial.

To assess whether outcome of immediate implant placement and immediate provisionalization after 1year was non-inferior to immediate implant placement and delayed provisionalization regarding Marginal Bone Level (MBL). Forty patients with a failing tooth in the aesthetic zone were randomly assigned for immediate implant placement with immediate (n=20) or delayed (n=20) provisionalization. Follow-up was at 1month and after 1year. The study was powered to detect a difference in MBL of <0.9mm. Apart from MBL, soft tissue peri-implant parameters, aesthetic indexes and patient satisfaction were assessed. After 1year, MBL changes were -0.75±0.69 mesially and -0.68±0.65 distally mm for the immediate group and -0.70±0.64 and -0.68±0.64mm for the delayed group respectively (NS). Regarding differences in means, non-inferiority was observed after 1year (mesially: Group A versus B: difference in mean 0.08mm (95% CI -0.38 to 0.53, p=0.71 distally: Group A versus B: difference in mean 0.09mm (95% CI -0.37 to 0.56mm, p=0.66).No significant differences in the other outcome variables were observed. This study showed that immediate placement and immediate provisionalization was non-inferior to immediate placement with delayed provisionalization. In addition, although not powered for these outcome variables, no clinically relevant differences in other outcomes were observed (www.isrtcn.com: ISRCTN57251089).

A 5-year prospective radiographic evaluation of marginal bone levels adjacent to parallel-screw cylinder machined-neck implants and rough-surfaced microthreaded implants using digitized panoramic radiographs

ObjectiveThe purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level over five years of functional loading. Materials and methodsFrom January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until December 2011. Marginal bone level was radiographically determined at six time points: implant placement (baseline), after the healing period, after six months, and at two years, three years, and five years follow-up. ResultsMedian follow-up time was 5.2 years (range: 5.1–5.4). The machined-neck group had a mean crestal bone loss of 0.5 mm (0.0–2.3) after the healing period, 1.1 mm (0.0–3.0) at two years follow-up, and 1.4 mm (0.0–2.9) at five years follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (−0.4 to 2.0) after the healing period, 0.5 mm (0.0–2.1) at two years follow-up, and 0.7 mm (0.0–2.3) at five years follow-up. The two implant types showed significant differences in marginal bone levels. ConclusionsRough-surfaced microthreaded design caused significantly less loss of crestal bone levels under long-term functional loading in the mandible when compared to machined-neck implants.

Retrospective Results of Implants for Partially Edentulous Posterior Jaws According to Time Points of Early Loading

This study evaluated the survival and success rates and marginal bone loss conditions of early loaded implants in the posterior maxilla and mandible of partially edentulous patients. Implants (n = 299) were placed in 105 patients at two research centers. Provisional fixed dental prostheses were provided to the patients between 1 week and 2 months after implant placement. The implants were classified into four groups according to the loading time (1 to 2, 2 to 4, 4 to 6, and 6 to 8 weeks). Periapical radiographs were taken via a parallel imaging technique, and the peri-implant marginal bone level was measured on the radiographic images. Most implants were lost within 1 month, and one implant was removed at 36 days after loading. The cumulative survival rate of the implants was 97.0%. Implants loaded in the maxilla at 1 to 2 weeks after prosthesis insertion had significantly lower survival rates than any other group (P = .013). There were no significant differences in marginal bone levels among the implant groups classified according to loading time. Early loading is a safe and predictable procedure for implant-supported restoration of posterior partial edentulism. However, care must be taken in early loading within 2 weeks after maxillary implant insertion.

The Evaluation of the Success of Immediately Placed Single Implants: A Retrospective Clinical Study

: The aim of this retrospective clinical trial was to evaluate the survival rates and the marginal bone levels of immediately placed implants in fresh extraction sockets in a period of 36 months. : One hundred seventeen patients who had received 165 immediately placed implants and followed up for 36 months after loading were included in this retrospective study. Survival rate and mesial and distal marginal bone levels of all implants were determined with the measurements made on periapical radiographs at baseline and recall evaluations. : The results of clinical evaluation showed a survival rate of 93.94%. Ten of 165 implants failed: 7 implants in female patients indicating 90.28% survival rate and 3 male patients with 93.4% survival rate. The mean age of patients with implant failure was 60.8 years. No statistically significant differences in marginal bone levels with respect to localization, age, gender, grafting, and implant brands were noted. Grafting did not influence plaque index, gingival index, and periimplant probing depth in a statistically significant way. : The results suggest that immediately placed single implants show acceptable survival rates and mesial and distal marginal bone levels in 36-month follow-up period.

Radiographic evaluation of marginal bone levels adjacent to parallel‐screw cylinder machined‐neck implants and rough‐surfaced microthreaded implants using digitized panoramic radiographs

The purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level during a stress-free healing period and under functional loading. From January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until February 2008. The marginal bone level was radiographically determined, using digitized panoramic radiographs, at four time points: at implant placement (baseline level), after the healing period, after 6 months of functional loading, and at the end of follow-up. The median follow-up time was 1.9 (range: 1.9-2.1) years. The machined-neck group had a mean crestal bone loss of 0.5 mm (range: 0-2.3) after the healing period, 0.8 mm after 6 months (range: 0-2.4), and 1.1 mm (range: 0-3) at the end of follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (range: -0.4-2) after the healing period, 0.4 mm (range: 0-2.1) after 6 months, and 0.5 mm (range: 0-2.1) at the end of follow-up. The two implant types showed significant differences in marginal bone levels (healing period: P=0.01; end of follow-up: P<0.01). Radiographic evaluation of marginal bone levels adjacent to machined-neck or rough-surfaced microthreaded implants showed that implants with the microthreaded design caused minimal changes in crestal bone levels during healing (stress-free) and under functional loading.

A 4‐Year Prospective Clinical and Radiological Study of Maxillary Dental Implants Supporting Single‐Tooth Crowns Using Early and Delayed Loading Protocols

Recent studies have showed that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for standard two-stage procedures, especially in the mandible. However, there are only a few studies regarding the immediate/early loading of maxillary implants supporting single-tooth crowns. The aim of this study was to compare the clinical and radiological outcomes of early- and delayed-loaded dental implants supporting single-tooth crowns in the maxilla. Twenty-nine patients were consecutively treated between 2000 and 2002 with 59 Brånemark System MK III TiUnite implants (Nobel Biocare AB, Göteborg, Sweden) in the maxilla. Two groups were formed according to the loading protocols. In the test group, definitive implant-supported single crowns were delivered to 19 patients 6 weeks after the implant placement. In the control group, definitive implant-supported single crowns were delivered to 10 patients 6 months after the implant placement. Clinical and radiographic parameters were recorded at baseline, 1 to 4 years. Implant stability measurements have only been performed at 4-year follow-up recall. Overall, three implants were lost during the study period. Two implants were lost in the test group including 36 implants, which indicated a survival rate of 94.4%. One of the lost implants was replaced and then osseointegrated successfully. One implant was lost in the control group during the healing period, which indicated a survival rate of 95.7%. The average marginal bone loss was 1.11 mm for 56 implants after 4 years. There were no significant differences in marginal bone levels, insertion torque, and resonance frequency values between the two groups. The results of this study indicate that 6 weeks of early loading period for TiUnite-surface titanium implants in the maxilla is reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.

Histologic Evaluation of Implants Following Flapless and Flapped Surgery: A Study in Canines

Flapless surgery requires penetration of the alveolar mucosa and bone without reflection of mucoperiosteal flaps. Do these techniques force gingival tissue or foreign materials into osteotomies? If so, do such tissues or materials interfere with osseointegration? A proof-of-principle study using a canine model attempted to answer these questions. Five young adult Hound Labrador mongrel dogs received implants with a moderately roughened surface by anodic oxidation using flapless or conventional one-stage (control) surgery in contralateral jaw quadrants. The implants were placed into the osteotomies, and the international stability quotient (ISQ) was recorded using resonance frequency analysis. These measurements were repeated following a 3-month healing interval when the animals were euthanized, and implants and surrounding tissues were retrieved and processed for histologic analysis. The implants were stable upon insertion and demonstrated increased stability at 3 months without significant differences between surgical protocols. The histologic evaluation showed high bone-implant contact (flapless surgery: 54.7% +/- 8.4%; control: 52.2% +/- 13.0%; P >0.05) without evidence of gingival tissue or foreign body inclusions. There were no significant differences in marginal bone levels between the surgical protocols. Post-insertion and at 3 months, ISQ values depended on the amount of torque delivered. Immediately post-insertion, for every 1-unit increase in torque value, the ISQ increased by 0.3 (95% confidence interval: 0.1 to 0.4; P = 0.0043). Three months postoperatively, for every one-unit increase in torque the ISQ value decreased 0.2 (95% confidence interval: -0.4 to -0.1; P = 0.0012). The effect of torque on ISQ values was independent of treatment effects and remained significant after adjustment for treatment. The results suggest that implants placed without flap reflection remain stable and exhibit clinically relevant osseointegration similar to when implants are placed with flapped procedures. Greater torque at implant placement resulted in less implant stability at 3 months.

Influence of smoking on marginal bone loss and tooth loss--a prospective study over 20 years.

The aim was to investigate the influence of smoking on longitudinal marginal bone loss and tooth loss in a prospective study over 20 years. In addition, the effect of cessation of smoking on bone loss and the interaction between smoking, plaque and marginal bone loss were evaluated. A total of 507 dentate individuals from an epidemiological study were examined in 1970 and 1990. The clinical investigation included registration of number of remaining teeth and presence of plaque. The marginal bone level was determined by assessments on the proximal surfaces on the radiographs from 1970 and 1990. The marginal bone loss was defined as the difference in marginal bone level over 20 years. The subjects were interviewed about smoking habits. Stepwise multiple regression analyses were adopted to calculate the influence of the independent variables on longitudinal marginal bone loss and tooth loss. In 1970, 50.7% of the subjects were smokers, while the corresponding relative frequency in 1990 had decreased to 31.0%. Smoking was significantly correlated to an increased marginal bone loss over 20 years. Individuals who stopped smoking between 1970 and 1990 lost significantly less marginal bone during this period than those who declared that they smoked during the 20-year period. Smoking was not found to be significantly correlated to tooth loss over 20 years. The results support the hypothesis that smoking is a significant risk factor of periodontal disease.