Randomized controlled trial comparing immediate loading with conventional loading using cone-anchored implant-supported screw-retained removable prostheses: A 2-year follow-up clinical trial

Statement of problem

Implant-based prosthetic solutions can be time consuming. If implants can be loaded immediately, treatment time can be reduced.

Accuracy of partially and fully guided surgical techniques for immediate implant placement: An in vitro assessment

Statement of problemOptimal implant positioning is essential to achieving predictable results. Computer-guided surgery has been reported to be an accurate technique for implant placement in healed sites, but the accuracy of guided techniques for immediate implant placement into fresh sockets is still unclear.PurposeThe purpose of this experimental randomized split-mouth study in pig jaws was to determine the accuracy of partially and fully guided surgical techniques for immediate implant placement into fresh sockets and to compare 2 different methods of implant position deviations analysis.Material and methodsTwenty implants were installed in 10 pig jaws using 2 different techniques: partially guided (n=10) and fully guided (n=10). Cone beam computed tomography and digital scanning were performed before and after the surgical procedure to plan the virtual implant position and fabricate the surgical guide, as well as to determine implant position deviations. Two methods were used to evaluate implant deviations: tomographic and digital scanning. The Shapiro-Wilk test of normality was used. Deviation comparisons were carried out by using paired t tests (α=.05), and intraclass correlation coefficient (ICC) was computed to assess the agreement between the 2 methods of implant deviation analysis.ResultsIn the tomographic analysis, the partially guided technique resulted in significantly higher global apical and lateral coronal deviations (2.25 ±0.59 mm; 0.96 ±0.55 mm) than fully guided (1.52 ±0.89 mm; 0.75 ±0.52 mm) (P<.01 and P<.05, respectively). The analysis performed using digital scanning showed significantly higher angular, global apical, and lateral apical deviations in the partially guided (6 ±3.28 degrees; 2.49 ±1.03 mm; 2.16 ±1.07 mm) technique than in the fully guided (3.32 ±1.84 degrees; 1.5 ±0.58 mm; 0.98 ±0.67 mm) (P<.05). An ICC of 0.522 between the 2 methods of implant deviation analysis was obtained.ConclusionsThe partially guided technique was less accurate than the fully guided technique for immediate implant placement into fresh sockets. A moderate concordance was observed between cone beam computed tomography and digital scanning analyses, suggesting that more studies are required to validate and to define the most reliable method of measuring implant deviation.     

A prospective multicenter evaluation of immediately functionalized tapered conical connection implants for single restorations in maxillary anterior and premolar sites: 3-year results

Objectives

This multicenter prospective clinical trial investigated immediately provisionalized, anodized, conical connection, tapered implants with platform shifting in maxillary anterior and premolar sites.

Materials and methods

Patients requiring single-tooth implant-supported restorations in maxillary anterior and premolar sites were enrolled. Implants were immediately provisionalized and evaluated at insertion, 6 months, and annually thereafter. Outcome measures were marginal bone level change (ΔMBL), cumulative survival rate (CSR), and success rate, soft-tissue parameters, and oral health impact profile (OHIP). ΔMBL and Pink Esthetic Score were analyzed using Wilcoxon signed-rank tests. CSR was calculated using life table analysis. Other soft-tissue parameters were analyzed using sign tests.

Results

Of 94 enrolled patients (99 implants), 84 (88 implants) attended the 3-year follow-up. After an initial bone loss between implant insertion and 6 months (− 0.92 ± 1.23 mm), bone levels stabilized from 6 months to 3 years (0.13 ± 0.94 mm) with no significant change. The 3-year CSR was 98.9%, and the cumulative success rate was 96.9%. Papilla index scores of 2 or 3 were observed at 88.6% of sites at the 3-year visit compared with 32.8% at implant insertion. Improvements were observed for all other outcomes, including bleeding on probing, esthetics, plaque, and OHIP.

Conclusions

This restorative protocol was associated with high primary stability, patient satisfaction, stable bone levels, and an overall improvement of the soft tissue outcomes over a 3-year period.

Clinical relevance

The presented treatment is a viable option for single-tooth restorations of maxillary anterior teeth and premolars with successful short- to mid-long-term clinical outcomes.

     

Astra Tech and Brånemark System implants: a prospective 5-year comparative study. Results after one year

Background: Endosseous dental implants are used frequently, and many implant systems are available. The scientific documentation of the implant system presents a great variation, and it is often difficult to compare studies of different systems. Purpose: The aim of this study was to compare two Swedish implant systems (Astra Tech and Brånemark System± implants), in a prospective randomized study. Materials and Methods: Sixty-six patients were equally distributed between the two implant systems; 184 Astra Tech and 187 Brånemark System implants were used. The patients have been followed annually with clinical and radiographic examinations. The results after 1 year are reported. Results: The abutment procedure was found to be easier and less time-consuming with Astra Tech than with Brånemark implants. The operation times in minutes (mean ± SEM) were for the respective implant 35 ± 4.0 and 51 ± 4.8 in the maxilla and 32 ± 3.8 and 43 ± 2.4 in the mandible. The differences in both cases were significant: p <.02 and p <.05, respectively. The failure rate for Astra Tech implants was 0.5% and for Brånemark implants 4.3%. The difference was significant (p <.05); however, taking into account that five of the eight implant losses in the Brånemark implant group occurred in one patient, an intraindividual correlation cannot be excluded. Therefore, this result should be interpreted with caution. The marginal bone level changes were examined already from the fixture installation. The major bone loss was found between fixture installation and baseline. This bone loss was several times greater than the bone loss between the baseline and the 1-year follow-up. The total bone loss during the observation period did not differ significantly between the systems, but they had different resorption patterns. The bone loss in the upper jaw between baseline and 1-year follow-up was 0.22 ± 0.14 and 0.03 ± 0.09 mm for the Astra Tech and Brånemark implants, respectively. In the lower jaw, the loss was -0.31 for both systems. The frequency of plaque accumulation and bleeding on probing did not differ between the implant systems. Conclusions: Abutment connection with Astra Tech implants was simpler than the corresponding surgery with Brånemark System implants and the survival rate of Astra Tech implants was higher than that of Brånemark system implants.     

Radiological and clinical follow-up of machined- and anodized-surface implants after mean functional loading for 33 months

Abstract: The purpose of this retrospective study was to compare peri‐implant bone loss and mucosal conditions around machined‐surface (MS) and anodized‐surface (AS) interforaminal implants in the mandible at least 30 months after placement. Fifty patients, each treated with four interforaminal screw‐type implants consecutively, were included. Thirty‐one patients (62%) with a total number of 124 implants (64 MS and 60 AS implants, both Brånemark type MKIII) were available for follow‐up. Rotational panoramic radiographs were used for evaluating marginal bone loss. Clinically, marginal plaque index (mPI), bleeding on probing (BOP) and pocket probing depth (PPD) were evaluated. AS implants showed significantly less marginal bone loss than MS implants (−1.17±0.13 vs. −1.42±0.13 mm; P=0.03). Marginal bone loss around distal implants was less pronounced at AS implants (−1.05±0.14 mm) when compared with MS implants (−1.46±0.14 mm; P=0.05). Within the smoking group, there was less peri‐implant bone loss around AS implants than around MS implants (−1.08±0.27 vs. −1.83±0.2; P=0.04). No differences between MS and AS implants were found with respect to mPI (57% vs. 67%), BOP (21% vs. 17%) and mean PPD (2.59±0.29 vs. 2.56±0.28 mm). Overall, both types of implants, in combination with bar‐supported overdentures, can produce excellent long‐term results in the interforaminal edentulous mandible with less peri‐implant bone loss around rough implant surfaces, which had beneficial effects at distal implants and in smokers.     

The water content in human gingival tissue

Abstract

Objective. The aim of this study was to investigate the various events occurring in unsplinted implant restoration in posterior jaws during a period of 4 years. Materials and methods. From August 2008 to April 2009, eight volunteers (three men and five women) who had two or more consecutively missing teeth received 20 implants in posterior maxillae and mandibles. Unsplinted single crowns were delivered to each implant. For the 4-year follow-up periods, patients were enrolled in a maintenance schedule at 1, 3, 6, 12, 24, 36 and 48 months. The data, including a questionnaire, radiography, mobility and probing were recorded on regular check-ups. Results. A total of 20 implants in eight patients were followed up for 48 months, showing a 100% survival rate. Mean marginal bone loss around implants was 0.26 mm. Statistical analysis revealed insignificant correlation between metal-ceramic and zirconia-ceramic crowns and among implant lengths (8.5 mm, 10 mm and 11.5 mm). Mean probing depths were similar or insignificantly different, regardless of the materials used or length of implants. The most frequent complications, in decreasing order, were food impaction (65%) and porcelain chipping (45%), sensitivity (25%), pain (20%) and loose contact (15%). Compared with metal-ceramic crowns, zirconia-ceramic crowns showed more unfavorable cases of porcelain chipping (p = 0.017), pain (p = 0.007) and loose contact with an adjacent crown (p = 0.031). Conclusions. Within the limits of the sample size, this study showed that unsplinted implant-supported single restorations to replace consecutive posterior missing teeth may function well.     

What Rôle do Treponema Vincenti play in Certain Diseases of the Gingiva

Abstract

Objective. The aim of this study was to use intra-oral radiographs to evaluate changes in marginal bone levels around three different implant designs after 1 year. Materials and methods. Three implant designs; two with a straight and one with a conical design, were placed adjacent to each other in the partially edentulous areas of 25 patients. The patients received 46 implants with a straight design (All fit SSO and SPI-element) and 29 implants with a conical design (SPI-contact). Two-way repeated analysis of variance (ANOVA) was used to evaluate the marginal bone changes in each group at 12 months follow-up (p < 0.05). Results. None of the implants had failed by the end of this study. After 12 months, significant differences were noted in the amount of alveolar bone loss recorded between the All fit SSO and SPI implants (p < 0.05). Mean crestal bone loss was 0.88 ± 0.43 mm for the All fit, 0.61 ± 0.34 mm for the SPI contact and 0.54 ± 0.27 mm for the SPI element implants. Conclusions. The results of this study demonstrate that straight (cylindrical) implants with shorter high polish surface displayed less bone resorption.     

Long-term follow-up of turned single implants placed in periodontally healthy patients after 16-22 years: radiographic and peri-implant outcome

Objectives: Retrospectively evaluate the survival, radiographic and peri‐implant outcome of single turned Brånemark^? implants after at least 16 years. Materials and methods: From 134 patients (C‐group), 101 could be contacted concerning implant survival and 50 (59 remaining implants) were clinically examined (I‐group). Marginal bone level was radiographically measured from the implant–abutment junction at baseline (=within 6 months after abutment connection) and 1–4, 5–8 and 16–22 years post‐operatively. Probing depth, gingival and plaque index were measured. Marginal bone‐level changes were analyzed using Friedman's and Wilcoxon's signed ranks tests. Spearman's correlations between radiographic and clinical parameters were calculated. Results: In the C‐group, 13 out of 166 implants in 11 out of 134 patients failed (CSR=91.5%). In the I‐group (28 males–22 females; mean age 23.9 years at baseline; range 14–57), the mean follow‐up was 18.4 years (range 16–22). The mean bone level was 1.7±0.88 mm (range ?0.8 to 5) after 16–22 years. Changes in the mean marginal bone level were statistically significant between baseline and the second measuring interval (1–4 years). Thereafter, no significant differences could be demonstrated. The mean interproximal probing depth, gingival and plaque indices were 3.9±1.27 mm, 1.2±0.81 and 0.2±0.48, respectively. Probing depth was moderately correlated with gingival inflammation (r=0.6; P<0.001) but not with bone level (P>0.05). 81.4% of the implants had a bone level ≤2nd thread and 91.5% had a probing depth ≤5 mm. 76.3% had both bone level ≤2nd thread and probing depth ≤5 mm. Conclusions and clinical implications: The single turned Brånemark^? implant is a predictable solution with high clinical survival and success rates. In general, a steady‐state bone level can be expected over decades, with minimal signs of peri‐implant disease. A minority (5%), however, presents with progressive bone loss. To cite this article :
Dierens M, Vandeweghe S, Kisch J, Nilner K, De Bruyn H. Long‐term follow‐up of turned single implants placed in periodontally healthy patients after 16–22 years: radiographic and peri‐implant outcome.
Clin. Oral Impl. Res. 23 , 2012; 197–204. doi: 10.1111/j.1600‐0501.2011.02212.x     

Maxillary implant overdentures retained by use of bars or locator attachments: 1-year findings from a randomized controlled trial

PurposeComparison of outcomes of maxillary implant overdentures retained by use of either locator attachments or bars in a 1-year randomized controlled trial.MethodsFifty edentulous participants received four maxillary implants. They were allocated to two groups (n = 25) differing in type of prosthetic attachment used to retain the maxillary prosthesis: either locator attachments or bars were applied. After one year, implant and overdenture survival was assessed. Peri-implant hygiene (Plaque-index, presence of calculus), soft tissue conditions (Gingiva-index, Sulcus Bleeding-index and pocket probing depth) and patient satisfaction (oral health impact profile (OHIP-49), denture complaints questionnaire and general satisfaction score (GSS)) were compared. The peri-implant bone level was estimated using intra-oral radiographs (student T-test).ResultsImplant survival was 96.7% in the locator group and 97.9% in the bar group. No overdentures had to be remade. Patient satisfaction was significantly greater in the bar group when rated by OHIP-49 sum score and by GSS. When comparing the denture complaints questionnaire and the separate OHIP-49 item scores, no significant difference was found. There was not a significant difference in hygiene and soft tissue conditions. Marginal bone loss was estimated 0.58 ± 0.71 mm for locators and 0.31 ± 0.47 mm for bars.ConclusionsMaxillary overdentures on four implants retained by bars or locators were compared. Bone loss was within an acceptable range for both groups after 1 year. However, less bone was lost in the bar group. Even though both treatment options improved patient satisfaction, bars seem to be particularly beneficial with regard to OHIP-49 sum score.     

Il rialzo del seno mascellare con osso bovino deproteinizzato: studio clinico prospettico

ObjectivesThe aim of this study was to evaluate success and survival rates of implants inserted following maxillary sinus lift procedures in patients with a residual bone height of up to 6 mm, a residual bone width of at least 5 mm, and preservation of normal intermaxillary relationships.Materials and methodsWe performed 68 maxillary sinus lifts in 60 patients. Bovine bone mineral was the only graft material used. In subsequent surgical procedures, a total of 120 implants were inserted, and prosthetic loading was done 5 months after implant placement.ResultsAll sinus grafts showed evidence of full integration. The mean follow-up after prosthetic loading was 24 months. The mean (± SD) marginal bone loss was 0.85 mm (± 0.36 mm). The overall implant survival and implant success rates were 100% and 97.5%, respectively.ConclusionsThe results of this study seem to confirm that use of bovine bone mineral as the sinus graft material offers reliable and predictable results in terms of the survival and success of dental implants in the atrophic posterior jaw.     

Clinical and radiographic study of implant treatment outcome in periodontally susceptible and non-susceptible patients: a prospective long-term study

Objectives: To evaluate the implant survival rate, periodontal and radiographic parameters of non‐submerged screw implants with two different surfaces (TPS and SLA) in periodontally non‐susceptible patients (NSP) and in patients with chronic adult periodontitis (CAP) or with generalized aggressive periodontitis (GAP). Material and methods: In 110 healthy partially edentulous subjects, 68 patients with CAP and 16 patients with GAP, a total of 513 implants were installed and followed for on average 48.1±25.9 months. Only fixed partial dentures were used as suprastructures. All patients were offered a supportive periodontal maintenance program. Smoking habits, health impairment, plaque score, bleeding on probing (BOP), type of surface, bone score, bone loss on radiographs and the number of failed implants were noted. Results: Implant survival in the NSP and CAP group was 98% and 96% after 140 months (NS), but only 80% after 100 months in the GAP group (P=0.0026). The overall rate of implant loss was 4.7%, but 15.25% in the GAP group (6/16 patients). The average marginal bone loss for all implants was 0.12±0.71 mm on the mesial side and 0.11±0.68 mm on the distal side. Bone loss/year was 0.08±0.31 and 0.07±0.3 mm in the NSP group, but 0.17±0.2 and 0.17±0.19 mm in the GAP group. Only in the GAP group, was bone loss significantly related to BOP, age, inflammation, presence of plaque, probing depth. Implants with a TPS surface had a lower survival than implants with an SLA surface (93% vs. 97%; P=0.06), especially in the GAP group (80% vs. 83%; P=0.005). Smoking habits had a significant influence on implant survival only in the GAP group (P=0.07), declining in current smokers to 63%, and to 78% in former smokers. Overall, impaired general health had no significant influence (P=0.85). However, impaired health further reduced implant survival in the GAP group (survival: 71%). In a statistical model to predict the chance for implant failing, only periodontal classification (P=0.012) and implant surface type (P=0.027) were significant. Conclusion: Periodontally healthy patients and patients with CAP show no difference in peri‐implant variables and implant survival rate, but patients with GAP have more peri‐implant pathology, more marginal bone loss and a lower implant survival implant rate. SLA surface had a better prognosis than the TPS surface.     

A 4‐ to 5‐Year Retrospective Clinical and Radiographic Study of Neoss Implants Placed with or without GBR Procedures

Background: New dental implant systems are continuously introduced to the market. It is important that clinicians report their experiences with these implants when used in different situations. Aim: The study aims to report the outcomes from a retrospective study on Neoss implants when used with or without guided bone regeneration (GBR) procedures. Materials and Methods: The study group comprised of 50 consecutive patients previously treated with 183 Neoss implants (Neoss Ltd., Harrogate, UK) in 53 sites because of single, partial, or total tooth loss. Implants were placed in healed bone in 23 sites, while a GBR procedure was used in 30 sites in conjunction with implant placement. A healing period of 3 to 6 months was utilized in 45 sites and in 8 sites a crown/bridge was fitted within a few days for immediate/early function. The number of failures, withdrawn and dropout implants was analyzed in a life‐table. All available intraoral radiographs from baseline and annual check‐ups were analyzed with regard to marginal bone level and bone loss. Results: A cumulative survival rate (CSR) of 98.2% was found for the non‐GBR group and 93.5% for the GBR group with an overall CSR of 95.0% after up to 5 years of loading. In spite of the failures, all patients received and maintained their prostheses. Based on all available radiographs, the bone level was situated 1.3 ± 0.8 mm (n = 159) below the top of the collar at baseline and 1.7 ± 0.8 mm (n = 60) after 5 years of follow‐up. Based on paired baseline and 1‐year (n = 70) and 5‐year radiographs (n = 59), the bone loss was found to be 0.4 ± 0.9 and 0.4 ± 0.9 mm, respectively. There were no statistically significant differences between GBR and non‐GBR sites with regard to implant survival or bone loss. Conclusions: The Neoss implant system showed good clinical and radiographic results after up to 5 years in function.     

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.     

Impact of the outcome of guided bone regeneration in dehiscence-type defects on the long-term stability of peri-implant health: clinical observations at 4 years

Objectives: To investigate the impact of residual defect height (RDH) following guided bone regeneration (GBR) in dehiscence‐type defects on the long‐term stability of peri‐implant health after a period of 4 years. Material and methods: The RDH values in dehiscence‐type defects at titanium implants were clinically assessed after 4 months of submerged healing following augmentation using a natural bone mineral (NBM) and a randomized application of either a cross‐linked‐ (VN) or a native collagen membrane (BG) (n=12 patients each). The RDH values were classified as absent (0 mm, control; n=8), minimal (1 mm, test 1; n=8), or advanced (>1 mm, test 2; n=8). Clinical parameters (i.e. bleeding on probing [BOP], probing pocket depth [PD], mucosal recession [MR]) were recorded (mesio‐, mid‐, and disto‐buccal aspects) at 4 years after prosthesis installation. Results: The mean PD (2.9±0.7, 2.8±0.7, 2.7±0.8 mm) values at 4 years were comparable in all the groups investigated. The mean MR values tended to be increased in both the test groups (0.5±0.7, 0.4±0.6 mm, respectively), when compared with the control group (0.2±0.3 mm) (P>0.05, respectively). The mean BOP values were also increased in both the test groups (45.8±30.5%, 54.1±24.8%, respectively), even reaching statistical significance when comparing test 2 and control (29.1±21.3%) groups (P=0.02). Conclusion: The present study indicated that (i) implants exhibiting RDH values >1 mm are at a higher risk of developing peri‐implant disease and (ii) positive RDH values may be associated with an increase in MR and may therefore compromise the overall esthetic outcome of implant therapy. To cite this article:
Schwarz F, Sahm N, Becker J. Impact of the outcome of guided bone regeneration in dehiscence‐type defects on the long‐term stability of peri‐implant health: clinical observations at 4 years. Clin. Oral Impl. Res 23 , 2012; 191–196.
doi: 10.1111/j.1600‐0501.2011.02214.x     

Narrow‐ (3.0 mm) Versus Standard‐Diameter (4.0 and 4.5 mm) Implants for Splinted Partial Fixed Restoration of Posterior Mandibular and Maxillary Jaws: A 5‐Year Retrospective Cohort Study

Background: Evidence concerning predictability of narrow‐diameter implants (NDIs) (<3.3 mm) to restore partially edentulous posterior maxillary and mandibular areas is limited. The aim of this study is to compare the 5‐year outcomes of NDIs (3.0 mm) and standard‐diameter implants (SDIs) (4.0 to 4.5 mm) supporting fixed partial dentures (FPDs) in posterior mandibular and maxillary jaws. Methods: All patients treated with at least two adjacent NDIs or SDIs according to available bone thickness and with a minimum follow‐up of 5 years after placement were invited to undergo a clinical and radiologic examination. Outcome measures were implant and FPD failures, biologic and prosthetic complications, and marginal bone loss. Results: A total of 107 out of 127 patients attended the examination: 49 (113 implants) of the NDI group, and 58 (126 implants) of the SDI group. Two NDIs failed in one patient versus four SDIs in four patients (P = 0.37). One FPD failed in the NDI group versus two FPDs in the SDI group (P >0.99). Nine biologic complications occurred in the NDI group and twelve in the SDI group (P = 0.81). Twelve prosthetic complications occurred in the NDI group and only two in the SDI group (P = 0.001). Peri‐implant marginal bone loss at 5 years was 0.95 ± 0.84 mm for the NDI group and 1.2 ± 0.86 mm for the SDI group (P = 0.06). Conclusion: Five‐year data indicate that FPD treatment in posterior mandibular and maxillary jaws with NDIs was as reliable as with SDIs, although NDIs showed a higher risk of prosthetic complications.     

A 1‐Year Controlled Clinical Trial of Immediate Implants Placed in Fresh Extraction Sockets: Stability Measurements and Crestal Bone Level Changes

Purpose: The aim of this study was to measure stability and crestal bone level changes of implants placed in fresh extraction sockets in elderly patients. Methods: Thirty‐five patients who were in need of tooth extractions were recruited for this study. They received a total of 65 implants in both jaws to support fixed or removable prostheses. The teeth were carefully extracted, the implants set directly in the root socket, and resonance frequency analysis (RFA) measurements were simultaneously performed (Time 1 = T1). After a healing time of 6 to 10 weeks the measurements were repeated (Time 2 = T2). Orthograd periapical radiographs were taken when the new prostheses were fabricated and after 1 year of loaded period. The distance between the first visible bone implant contact (BIC) and the implant‐shoulder was measured and crestal bone loss was calculated (ΔBIC). Mean RFA and BIC were compared for various subgroups (p < .05). By means of a fixed effects model, the impact of the parameters gender, jaw, and prosthetic indication on RFA measurements was analyzed (p < .016). Results: The mean implant stability quotient (ISQ) values were 64.4 ± 6.7 at T1 and 64.0 ± at 8.6 T2, with a trend to higher values for male patients. The mixed model showed that only the jaw had a statistically significant impact on ISQ values, with higher values for the mandible. Mean crestal bone loss was small with 0.49 ± 0.81 mm, ranging form 0.1 to 2.4 mm. Twenty percent of the implant sites lost more than 1‐mm crestal bone. No differences were found in subgroups. Conclusions: Good primary and secondary stability of the implants was reached in both jaws. Crestal bone loss was small but may not be fully predictable for a single site. This treatment modality can be applied successfully in elderly patients and can be suggested for various prosthetic indications in both jaws.     

A 5-year prospective clinical and radiographic study of non-submerged dental implants

Osseointegrated implants as anchors for various prosthetic reconstructions have become a predictable treatment alternative. It was expected that implants required submucosal placement during the healing period for successful tissue integration. However, it has been demonstrated that healing and long-term health of implants could be achieved with equal predictability in a 1-stage, non-submerged approach. This prospective 5-year study not only calculates implant success by life table analysis, but also evaluates the correlation between observed bone level changes with clinical parameters as measured by suppuration, plaque indices, bleeding indices, probing depth, attachment level and mobility. A total of 112 ITI dental implants were inserted in different areas of the jaws. Clinical and radiographic parameters were evaluated annually for 5 years, whereas a portion of the study group for which 6-year evaluations were available were included in the life-table analysis. The overall success rate after 5 years in service was 99.1%, while after 6 years it was reduced to 95.5% due to the fracture of 3 implants in 1 patient. The mean crestal bone loss experienced during the first year was 0.6 mm followed by an annual yearly loss of approximately 0.05 mm. No significant differences could be found between the amount of bone loss measured at each of the yearly follow-up visits. This suggests that statistically the followed implants did not show any radiographically measurable bone loss following the initial period of bone loss associated with implant placement and osseointegration. Low levels of correlation between the individual and cumulative clinical parameters with radiographically measured bone loss suggests that these parameters are of limited clinical value in assessing and predicting future peri-implant bone loss.     

Osseointegrated implants in edentulous jaws: a 2-year longitudinal study

Osseointegrated implants in 50 edentulous jaws were studied during a 2-year observation period. The implant survival rate was 89% in the maxillae and 97% in the mandibles. The marginal bone loss averaged 1.7 mm in the maxillae and 1.1 mm in the mandibles. Most of this bone loss occurred during the first year. The bone loss was greater in jaws with a preoperatively minor resorption of the alveolar ridge than in those with moderate or advanced resorption. The bone loss was also greater at the medially positioned implants than at those more posterior.     

Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Saddle‐type defects were prepared in the lower jaws of 6 fox hounds and randomly filled with a natural bone mineral (NBM) and a biphasic calcium phosphate (SBC) and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, respectively, dissected blocks were processed for histomorphometrical analysis (e.g., mineralized tissue [MT], bone‐to‐implant contact [BIC]). Results: The mean MT values (mm²) and BIC values (%) tended to be higher in the PEG groups (MT: NBM [3.4±1.7]; SBC [4.2±2]/BIC: NBM [67.7±16.9]; SBC [66.9±17.8]) when compared with the corresponding CM groups (MT: NBM [2.5±0.8]; SBC [2.3±1.6]/BIC: NBM [54.1±22.6]; SBC [61±8.7]). These differences, however, did not reach statistical significance. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. To cite this article :
Mihatovic I, Becker J, Golubovic V, Hegewald A, Schwarz F. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes.
Clin Oral Impl Res. 23 , 2012; 308–315.
doi: 10.1111/j.1600‐0501.2011.02238.x     

Evaluation of immediately loaded mandibular four vertical versus tilted posterior implants supporting fixed detachable restorations without versus with posterior cantilevers

Background

Distally inclining posterior implants may be technically challenging in certain situations. The presence of a posterior cantilever can also exert unfavorable forces on supporting implants. The aim of the present study was to evaluate and compare peri-implant soft and hard tissues around 4 mandibular interforaminal implants having tilted posterior implants with posterior cantilevers, versus vertical implants, 2 in the interforaminal region and 2 in the first molar regions, without posterior cantilevers. All implants supported full-arch fixed detachable restorations opposing complete dentures.

Material and methods

A total of 80 implants were placed flapless in the mandibles of 20 edentulous participants. Four implants were placed for every participant, who were randomly assigned into 2 equal groups. Axial group implants were vertically aligned, with 2 implants in the interforaminal area and 2 in the molar area. Tilted group implants have 2 anterior axial and 2 posterior distally inclined implants. Interim screw-retained prostheses converted from pre-existing dentures were immediately fabricated and loaded on the same day of surgery. After awaiting period of 3 months, all participants received fixed detachable metal acrylic resin definitive restorations. A follow-up protocol of 3, 6, and 12 months was scheduled to assess the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, and marginal bone level and bone density changes.

Results

No statistically significant differences (P?>?.05) were found in the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, bone density, and marginal bone level between the axial and tilted implant groups after the 1-year follow-up period.

Conclusion

Placing 4 flapless immediately loaded implants in mandibular edentulous patients that supported full-arch fixed restorations provided high implant and prosthodontic success rates whether posterior implants were tilted with posterior cantilevers or vertically aligned without posterior cantilevers.

Trial registration: Pan African Clinical Trial Registry database, PACTR201907776166846. Registered 3 July 2019, www.pactr.org.