Radiographic marginal bone level evaluation around two different tissue-level implant systems: a one-year prospective study.

BACKGROUND: Marginal bone loss, is a frequently reported variable in the evaluation of dental implants. The primary objective of this study was to evaluate radiographic marginal bone level changes around the two different tissue-level implant systems placed adjacently in the posterior maxilla or mandible. The influence of implant macro-geometry and vertical soft tissue thickness on marginal bone loss were also evaluated. METHODS: Seven patients were included in the study and a total of 18 implants were analyzed. Each patient received two different implants placed adjacently in the maxilla or the mandible. The implants used in our study were either Straumann® SP cylindrical implants or JD Octa® tapered implants. During the surgery, vertical soft-tissue thickness was measured with a periodontal probe placed on the top of the bony crest and in the center of the future implant site. Healing abutments were then seated. Three months following implant placement, impressions were taken, and screw-retained metal ceramic prostheses were delivered. Standardized intraoral radiographs were taken immediately after implant placement and one year following implant loading in order to assess marginal bone level changes. RESULTS: Results showed a mean marginal bone loss of 0.55±0.5 mm for Straumann® SP implants and 0.39±0.49 mm for JD Octa® implants after one year of loading and the difference was not statistically significant between the two systems. A statistically significant correlation was found between soft tissue thickness and marginal bone loss; in sites with thin mucosal tissues (≤2 mm), there was significantly greater bone loss compared to sites with thick, soft tissues (> 2 mm) in both implants. CONCLUSIONS: Radiographic marginal bone loss was not statistically different between the two implant systems at the one-year examination period. Moreover, vertical soft tissue thickness influenced marginal bone loss regardless of the implant system used.

Immediate fixed rehabilitation supported by pterygoid implants for participants with severe maxillary atrophy: 1-Year postloading results from a prospective cohort study.

STATEMENT OF PROBLEM: Few investigations concerning the use of pterygoid implants have reported reproducible and consistent data, making survival data controversial. PURPOSE: The purpose of this clinical study was to investigate the 1-year survival and success rates of pterygoid implants and prostheses in participants affected by severe atrophy of the posterior maxilla requiring a complete-arch immediate fixed prosthesis. MATERIAL AND METHODS: Fifteen participants, either completely edentulous or with failing dentition in the maxillary arch and with severe atrophy of the posterior maxilla, were enrolled in the study. All participants underwent prosthodontic rehabilitation after implant placement in both the anterior maxilla areas and the pterygoid regions. The survival data of the implants were evaluated at the time of abutment connection by means of a mobility test for each implant. After placement of the prostheses, survival was assessed by means of marginal bone maintenance as assessed by panoramic radiographs and the absence of pain or symptoms of infection. The t test was used for evaluating the difference in age between men and women (α=.05). Correlations between categorical variables (Fisher exact test) were used to evaluate the possible association between the number of implants and both the age and presence of comorbidities (α=.05). RESULTS: During the 1-year follow-up, high prosthesis stability and no implant loss were observed for all participants. In addition, participants did not report any pain or paresthesia. No peri-implant radiolucency was detected in the panoramic radiographs. Survival and success rates in the follow-up period were 100%. CONCLUSIONS: The present study supports the conclusion that pterygoid implants have a high success rate with minimal or no complications.

Immediate fixed rehabilitation of severe maxillary atrophies using trans-sinus tilted implants with or without sinus bone grafting: One-year results from a randomised controlled trial.

BACKGROUND: To compare the clinical outcomes between tilted trans-sinus implants inserted without simultaneous bone grafting versus sinus elevation procedures with bone grafting to support immediately loaded prostheses for the rehabilitation of the atrophic maxilla. MATERIALS AND METHODS: Thirty-two subjects were selected to receive an immediately loaded fixed restoration supported by four or six implants and randomised to receive at least one trans-sinus implant without simultaneous bone grafting (group 1, n = 16) or at least one trans-sinus implant with sinus elevation procedures and bone grafting (group 2, n = 16). Primary outcomes were prosthesis and implant failures. Secondary outcomes were complications and peri-implant marginal bone level changes. RESULTS: Forty-one trans-sinus implants (23 trans-sinus implants without simultaneous bone-grafting and 18 trans-sinus implants with sinus elevation procedures), 23 conventional tilted implants and 84 axial implants were inserted. No drop-outs occurred. At 1 year after loading no prosthesis was lost. One patient treated with sinus graft lost one implant (0.0% vs. 6.3%, difference 6.3%; 95% CI: -4.7 to 17.3; P = 0.99). There were no statistically significant differences in implant failures between the two groups. Complications occurred in eight patients in the group without bone grafting and in nine patients in the group with sinus elevation and bone augmentation. No statistically significant differences were found in complications (50.0% vs. 56.3%, difference 6.3%; 95% CI: -12.7 to 25.3; P = 0.99), and in peri-implant marginal bone level changes (difference 0.05 mm; 95% CI: -0.24 to 0.34; P = 0.604). CONCLUSIONS: In this study, no statistically significant differences were observed between subjects treated with tilted trans-sinus implants without simultaneous bone-grafting or with sinus elevation procedures supporting cross-arch immediately loaded fixed prostheses in atrophic maxillae. Longer follow-ups are needed and alternative procedures such us short implants or crestal sinus elevation procedures should be compared since they could be less invasive.

Guided bone regeneration in calvarial critical size bony defect using a double-layer resorbable collagen membrane covering a xenograft: a histological and histomorphometric study in rats.

PURPOSE: The aim of the present study was to evaluate histologically and histomorphometrically the bone regeneration in critical size calvarial defects in rats grafted with either a deproteinized bovine bone mineral (DBBM) alone or in combination with a single or double layer of native bilayer collagen membrane (NBCM). The secondary objective was to evaluate histologically and histomorphometrically the residual DBBM in these defects. MATERIAL AND METHODS: Thirty-two Wistar rats were divided into two groups: a control group of 16 rats with two critical size calvarial defects (CSD) of 5 mm performed each on either side of the median sagittal suture, where the frontal defect remained without any filling (negative control), while the occipital defect (positive control) was filled with DBBM; and then a test group of 16 rats, with two CSD filled with DBBM and covered by either a single (SM) or a double layer (DM) of NBCM. The animals were sacrificed at 4 and 8 weeks. RESULTS: At 1 month, the histological and histomorphometric analysis showed new bone formation (NBF) in the defects that received only DBBM, DBBM+DM, and DBBM+SM (11.5, 17.3, and 22.7%, respectively), while the negative control defects showed only 0.4% of new bone formation. At 2 months, the histological and histomorphometric analysis showed NBF in the defects that received only DBBM, DBBM+DM, and DBBM+SM (16.8, 24.5, and 37%, respectively), while the negative control defects showed only 0.9% of new bone formation. The residual xenogeneic material (RXM) was higher in defects covered by SM (30.2% at 1 month and 25.3% at 2 months) or DM (32.5% at 1 month and 28.5% at 2 months) compared with defects that were not covered by membranes (15.3% at 1 month and 9.4% at 2 months). CONCLUSIONS: This study demonstrated that GBR with a xenogeneic material in rat calvarial (CSD) of 5 mm requires the application of resorbable collagen membranes in either single or double layer, and a single layer alone is sufficient to promote this regeneration.

A comparison of two implants with conical vs internal hex connections: 1-year post-loading results from a multicentre, randomised controlled trial.

PURPOSE: To compare the clinical and radiological outcomes of identical implants with conical or internal hex connections. METHODS: A total of 90 patients with partial edentulism requiring one implant-supported prosthesis were randomly allocated in two equal groups (n = 45) to receive either implants with a conical connection or implants of the same type, but with an internal hex connection at three centres. Patients were followed for 1 year after loading. Outcome measures were implant failures, any complication and marginal bone level changes. RESULTS: One patient (2.2%) belonging to the internal hex group dropped out. One implant (2.2%) failed in the conical group. There were no statistically significant differences in implant failures between the two groups (2.2% vs. 0%, difference 2.2; 95% CI: -1.3; 5.7; P = 0.315). Two complications occurred in the conical group and two in the internal hex group (P = 1.000, difference 0.00, 95% CI: -3.1; 3.1). The 12-month peri-implant bone resorption was similar in both groups: 0.56 ±â€…0.53 mm (95% CI 0.03; 1.09) in the conical group and 0.60 ±â€…0.62 mm (95% CI 0.02; 1.22) in the internal hex group (difference = 0.04 ±â€…0.55, 95% CI: -0.51; 0.59, P = 0.745). CONCLUSIONS: Within the limitation of this study, preliminary short-term data (1 year post-loading) did not show any statistical differences between the two internal connection types, therefore clinicians could choose whichever connection they prefer. Conflict of interest statement: Tommaso Grandi serves as consultant for J Dental Care, Modena, Italy. This study was completely self-financed and no funding was sought or obtained, not even in the form of free materials.

Immediate, early (3 weeks) and conventional loading (4 months) of single implants: Preliminary data at 1 year after loading from a pragmatic multicenter randomised controlled trial.

PURPOSE: To compare the clinical outcome of single implants which underwent immediate nonocclusal loading with implants subjected to early non-occlusal loading at 3 weeks, and implants conventionally loaded at 4 months. MATERIALS AND METHODS: One hundred and five patients in five private practices requiring a single implant-supported crown were randomised to immediate loading (35 patients), early loading (35 patients) and conventional loading (35 patients) groups. To be immediately or early loaded, implants had to be inserted with a torque superior to 45 Ncm. Immediately and early loaded implants received non-occluding temporary crows, whereas conventionally loaded implants were directly restored with definitive crowns. Temporary crowns were replaced by definitive ones after 4 months. Outcome measures were crown and implant failures, complications and peri-implant marginal bone level changes recorded by a blinded assessor. RESULTS: Two patients dropped out from the immediate loading group up to 1-year post-loading. Two implants failed, one in the immediately loaded and one in the early loaded group (P=0.601). One immediately loaded implant and two early loaded implants were affected by one complication each (P=0.162). Mean peri-implant marginal bone loss after 1 year was -0.120±0.230 mm (95% CI -0.35, 0.10) for immediate, -0.390±0.840 mm (95% CI -1.23, 0.45) for early and -0.201±0.306 mm (95% CI -0.51; 0.11) for conventionally loaded implants. There were no statistically significant differences for any of the outcome measures between the three loading strategies up to 1-year post-loading. CONCLUSIONS: No major clinical differences were observed with regard to implant survival, complications and marginal bone level changes when loading single implants immediately, early or conventionally.

One abutment-one time versus a provisional abutment in immediately loaded post-extractive single implants: a 1-year follow-up of a multicentre randomised controlled trial.

PURPOSE: To compare immediately loaded post-extractive single implants using a definitive abutment versus provisional abutment later replaced by custom-made abutment. MATERIALS AND METHODS: In two private clinics, 28 patients in need of one single post-extractive implant in the maxilla or mandible from the left second premolar to the right second premolar area were randomised shortly before tooth extraction to provisional abutment (PA) and definitive abutment (DA) groups. Three patients had to be excluded for buccal wall fracture after tooth extraction. In the PA group, implants were immediately restored using a platform-switched provisional titanium abutment and definitive platform-switched titanium abutments were used in the DA group. In both groups, a non-occluding provisional single crown was provided. Implants were definitively restored after 4 months. In the PA group, the abutment was removed and the impression was made directly on the implant platform. In the DA group an impression of the abutment was made using a retraction cord. Outcome measures were: implant failures; complications; and marginal peri-implant bone level changes. Patients were followed up to 1 year after loading. RESULTS: Twelve patients were randomised to the DA group and 13 patients to the PA group. At the 12-month follow-up, no implant failed. One biological complication occurred in the DA group and one mechanical complication occurred in the PA group. All complications were successfully treated. One year after loading, implants in the DA group lost an average of 0.11 mm (SD: 0.06) of periimplant bone and implants in PA group about 0.58 mm (SD: 0.11). At the 12-month follow-up, there was a statistically significant difference in bone level change between groups (mean difference: 0.48 mm, CI 95% 0.40; 0.55, P < 0.0001). CONCLUSIONS: Within the limits of this study, the non-removal of abutments placed at the time of surgery resulted in the maintenance of 0.5 mm more bone levels around immediately restored postextractive single implants than repeated abutment removal, although this amount of bone maintenance may not have a clinical impact. Conflicts of interest notification: Dr Tommaso Grandi and Dr Paolo Guazzi serve as consultants for JDentalCare. This study was completely self-financed and no funding was sought or obtained, not even in the form of free materials.

A 3-year report from a multicentre randomised controlled trial: immediately versus early loaded implants in partially edentulous patients.

PURPOSE: To compare implant failure, prosthesis failure and radiographic bone level changes of immediate non-occlusal loading versus early loading in partially edentulous patients 3 years after implant placement. MATERIALS AND METHODS: A total of 80 patients with partial edentulism were selected for a two implant-supported immediate restoration and randomised to immediate loading (test group) or early loading (control group) after 2 months, 40 patients for each group. To be included in the study, implants had to be inserted with a torque ≥ 30 Ncm. In the test group, implants were provided with non-occluding temporary restorations. In the control group, healing abutments were attached and implants were left to heal nonsubmerged. Definitive prostheses were delivered 2 months after surgery with full occlusal contacts. The outcome variables were implant failure, prosthesis failure, complications and radiographic bone level changes at implants 3 years after loading. The assessor was blinded to group assignment. RESULTS: Eighty-one implants were immediately loaded and 80 were early loaded. Two immediately loaded patients and 1 early loaded patient dropped out at 3 years. No implant failed. Two complications occurred in the immediate loading group and 1 in the early loading group. There were no significant differences in bone levels changes at 36 months between the two groups (P = 0.67; difference 0.2 mm; 95% CI -0.23, 0.63). Immediately loaded implants lost 0.90 mm (95% CI 0.63, 1.17) and early loaded implants 1.10 mm (95% CI 0.81, 1.39). CONCLUSION: If adequate primary stability was achieved, no statistically significant difference in failure rates, complications or bone level changes between implants loaded immediately or early were observed 3 years after placement in partially edentulous patients.

Immediate provisionalisation of single post-extractive implants versus implants placed in healed sites in the anterior maxilla: 1-year results from a multicentre controlled cohort study.

PURPOSE: The purpose of the study was to compare the clinical and aesthetic outcome of single post-extractive implants versus implants placed in a preserved socket after 4 months of healing in the anterior maxilla. All of the implants were immediately non-occlusally loaded. MATERIALS AND METHODS: A total of 50 patients were treated in the two groups of study. The Delayed Group had a maxillary tooth (premolar, canine, lateral or central incisor) removed, with immediate socket grafting, followed by implant placement and provisionalisation 4 months later. The Immediate Group had immediate implant placement and provisionalisation. Outcome measures were implant failures, biological and biomechanical complications, peri-implant radiographic bone level changes, and gingival aesthetics. RESULTS: At the 12-month follow-up, two implants failed in the Immediate Group (8%) versus one in the Delayed Group (4%), with a comparable rate of implant failure (P = 0.55). No complications occurred for either group. The 12-month peri-implant bone resorption was similar in both groups (P = 0.23): 0.71 mm (95% CI 0.45, 0.97) in the Immediate Group versus 0.60 mm (95% CI 0.38, 0.82) in the Delayed Group. The mean difference in bone resorption was 0.13 mm (95% CI -0.21, 0.47). An ideal gingival marginal level was reached most frequently in the Delayed Group (83.3% versus 52.1%, P = 0.04). Rates of full closure of the papilla were similar between the two groups (82.6% for the Immediate Group versus 62.5% for the Delayed Group, P = 0.12). CONCLUSIONS: Given the limitation that this was not a randomised controlled trial, there were no differences in complications or crestal bone response at immediate post-extractive implants when compared to delayed implants. A delayed protocol might be considered in the aesthetic zone due to the gingival recession that occurs after post-extractive implant placement.

Immediate loading of four (all-on-4) post-extractive implants supporting mandibular cross-arch fixed prostheses: 18-month follow-up from a multicentre prospective cohort study.

AIM: To evaluate the outcome of immediately loaded mandibular cross-arch prostheses according to the 'all-on-4' concept supported by implants placed in fresh extraction sockets up to 18 months after loading. MATERIALS AND METHODS: In total, 47 patients with a mean age of 62.3 years (range 52 to 78) were rehabilitated with an immediately loaded fixed cross-arch prosthesis supported by four post-extractive implants. A total of 188 implants were inserted. Patients received a provisional fixed dental prosthesis with a metal framework within 48 hours after surgery and a permanent one 6 months later. The patients were evaluated clinically and radiographically at implant placement and at 6-, 12- and 18-month follow-up examinations. RESULTS: At the 18-month follow-up, no implant failed and all restorations were stable. Peri-implant bone levels amounted to 0.31 ± 0.12 mm after 6 months, 0.58 ± 0.112 mm after 12 months and 0.7 ± 0.107 mm after 18 months. No significant differences in bone loss were found between axially placed and tilted implants at the 6-month (0.06 mm; P = 0.115), the 12-month (0.12 mm; P = 0.062) and the 18-month follow-up (0.08 mm; P = 0.146). Three patients had a fracture of the provisional restoration, but all of the definitive prostheses remained stable throughout the study period without any complications. CONCLUSIONS: Within the limits of this study, it can be suggested that immediately loaded mandibular cross-arch fixed dental prostheses can be supported by four post-extractive implants, however larger and longer follow-ups are needed.

Immediate positioning of definitive abutments versus repeated abutment replacements in immediately loaded implants: effects on bone healing at the 1-year follow-up of a multicentre randomised controlled trial.

PURPOSE: To compare bone resorption around implants immediately loaded and restored using definitive abutments versus provisional abutments later replaced by custom-made abutments up to 12 months after implant placement. MATERIALS AND METHODS: 28 patients with partial edentulism were selected for a two-implant supported immediate restoration and randomised to provisional abutment (PA) and definitive abutment (DA) groups (14 patients for each group). In the PA group, implants were immediately restored using a platform-switched provisional titanium abutment. In the DA group, definitive platform-switched titanium abutments were tightened. In both groups, a provisional restoration was adapted, avoiding occlusal contacts. All implants were definitively restored after 3 months. In the PA group, patients underwent the standard prosthetic protocol: the abutments were removed and impressions were made directly on the implant platform. In the DA group, patients underwent the 'one abutment at one time' protocol: impressions were made of the abutments using a retraction cord. Peri-implant marginal bone levels were assessed immediately after surgery, and at 6- and 12-month follow-up examinations. RESULTS: At the 12-month follow-up no implant failed. In the PA group, peri-implant bone resorption was 0.359 mm after 6 months and 0.435 mm after 12 months. In the DA group, peri-implant bone resorption was 0.065 mm after 6 months and 0.094 mm after 12 months. There were statistically significant differences between the two groups for peri-implant bone level changes at the 6-month (P < 0.001) and the 12-month (P < 0.001) follow-up: 0.294 mm (CI 95% 0.276; 0.312) and 0.341 mm (CI 95% 0.322; 0.36), respectively. CONCLUSIONS: Within the limits of this study, it can be suggested that the non-removal of abutments placed at the time of surgery results in a statistically significant reduction of the crestal bone resorption around the immediately restored implants in cases of partial edentulism, however a difference of 0.3 mm may not have a clinical impact.

Immediate loading of two unsplinted implants retaining the existing complete mandibular denture in elderly edentulous patients: 1-year results from a multicentre prospective cohort study.

PURPOSE: To evaluate the outcome of two freestanding implants immediately loaded retaining an existing mandibular complete denture in elderly edentulous patients up to 1 year after loading. MATERIALS AND METHODS: 42 patients with a mean age of 76.5 years (range 71 to 89) were selected for stabilising their mandibular complete denture with two implants placed mesial to the mandibular canine position bilaterally. Individual ball abutments were connected and torqued at 30 Ncm and the existing complete denture was immediately attached. No postoperative limitations to chewing function were given. The patients were evaluated clinically and radiographically at implant placement and at 6- and 12-month follow-up examinations. RESULTS: At the 12-month follow-up no implant failed. Peri-implant bone resorption was 0.203 mm (CI 95% 0.322; 0.086) after 6 months and 0.298 mm (CI 95% 0.425; 0.173) after 12 months. Of the 42 cases, 3 had major prosthetic complications and 5 patients required minor extra maintenance appointments. CONCLUSIONS: Within the limits of this study, it can be suggested that the immediate loading of two unsplinted implants retaining the existing complete mandibular denture in elderly patients can result in favourable implant survival and peri-implant bone healing, however larger and longer follow-ups of 5 years or more are needed.

Immediate loading of single post-extractive implants in the anterior maxilla: 12-month results from a multicenter clinical study.

The purpose of the study was to evaluate survival and peri-implant bone levels of single, immediately loaded post-extractive implants in the anterior maxilla 12 months after implant placement. Thirty-six consecutive patients from 3 study centers were included in the study. The concerned sites were upper premolars, canines, and incisors. For each patient the following data were recorded: reason for tooth extraction, bone quality, implant size, and final insertion torque. Implants were placed using a flapless technique and immediately loaded with a nonoccluding temporary restoration. Final restorations were provided 4 months later. Peri-implant bone resorption was evaluated radiographically after 6 and 12 months. The average final insertion torque was 70.55 Ncm. One implant inserted in D3 quality bone with a 35-Ncm seating torque was lost. All other implants had a final insertion torque ranging between 50 and 80 Ncm. The average peri-implant bone loss was 0.437 and 0.507 mm at 6 and 12 months, respectively. All the sites maintained excellent papillae and peri-implant soft-tissue conditions. The resulting 1-year success rate was 97.2%. Immediate nonfunctional loading of single post-extractive implants in the anterior maxilla is a predictable treatment. And it seems that achieving high insertion torques by placing self-tapping/self-condensing implants in an underprepared osteotomy is favorable.