International Journal of Oral Implantology, 03/2013

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. Keywords: dental implants, early loading, follow-up, immediate loading, partial edentulism

Purpose: To evaluate the safety and clinical efficacy of a novel surface treatment (SurfLink®, Nano Bridging Molecules, Gland, Switzerland) on titanium dental implants. SurfLink consists of a monolayer of permanently bound multi-phosphonic acid molecules, which mimics the surface of naturally occurring hydroxyapatite. Materials and methods: Twenty-three patients requiring at least two single dental implants had their sites randomised according to a split-mouth design to receive one titanium grade 4 implant treated with SurfLink and one untreated control implant. Additional SurfLink-treated implants were placed if needed. Implants were submerged for 3 months in mandibles and 6 months in maxillae, were loaded with definitive metal-ceramic crowns, and followed up for 1 year after loading. Outcome measures were crown/implant failures, any complication, radiographic peri-implant marginal bone level changes and marginal bleeding. Results: One patient dropped out after abutment connection. All remaining patients were followed up to 1 year post-loading. No implant failed and only 1 postoperative complication (pain) occurred, but it may not have been related to the implant treatment. No bleeding was observed when a periodontal probe was used to examine the peri-implant soft tissues around the implants. There were no statistically significant differences in marginal bone level changes between the two groups (P = 0.057, mean difference = -0.27, SE = 0.13; 95% CI -0.55 to 0.01). Conclusions: Preliminary short-term data (1 year post-loading) of implants with a biomimetic monolayer of permanently bound multi-phosphonic acid molecules (SurfLink surface treatment) presented no safety issues. Clinical healing in both the control and SurfLink-treated implant group was uneventful and did not differ significantly between groups. More challenging clinical situations need to be investigated to evaluate the real effectiveness of this surface treatment. Keywords: biomimetic, dental implant, efficacy, multi-phosphonic acid surface treatment, safety

Purpose: To evaluate whether grafting with additional anorganic bovine bone to augment horizontally the buccal plate (internal and external grafting [IEG]) at single post-extractive implants preserves the alveolar ridge, improving aesthetics, better than internal socket grafting alone (ISGA). Material and methods: A total of 78 patients, treated in four Italian private practices, requiring a single immediate post-extractive implant, having at least 1 mm of implant-to-buccal bone gap after implant insertion and a preserved buccal bone, had the residual bone-to-implant gap filled with anorganic bovine bone. Thirty-nine randomly allocated patients received additional buccal horizontal augmentation of about 2 mm thickness with the same bone substitute (IEG group) covered with collagen resorbable membranes. Implants were submerged for 4 months before being loaded with provisional acrylic crowns. Definitive crowns were delivered after 6 months. Outcome measures were crown/implant failures, complications and aesthetics recorded by blinded assessors 6 months after initial loading, at delivery of definitive crowns. Results: Six months after initial loading, 8 patients dropped out, did not complete the treatment or were treated twice and therefore had to be excluded (4 from each group). There were no statistically significant differences for implant failures and complications between the two groups. Two implants failed in the IEG group versus 1 in the ISGA group. Four complications occurred, 2 in each group. The mean implant aesthetic score (IAS) was 7.8 at ISGA sites and 8.0 at IEG sites. There were no statistically significant differences between the two groups (P = 0.492; difference 0.2 mm; 95% CI -0.769, 0.369) for IAS score. There were no statistically significant differences in the outcomes between the centres. Conclusions: The use of adjunctive anorganic bovine bone placed buccally at preserved buccal sites of immediate post-extractive implants may not improve the aesthetic outcome, however additional research is needed to confirm or reject these preliminary findings. Keywords: aesthetics, anorganic bovine bone, bone augmentation, dental implants, post-extractive sites

Purpose: The aim of this triple-blinded randomised controlled trial was to test if argon plasma cleaning/ sterilisation of customised abutments can affect peri-implant marginal bone levels when compared to 5 seconds of steam cleaning. Materials and methods: A total of 20 consecutive periodontally healthy patients requiring single implant-supported restorations in the maxillary premolar or anterior area were selected. All patients received a single implant. At abutment connection, customised abutments were randomly allocated to control (subjected only to usually adopted steam cleaning, CG) and test groups (subjected to plasma cleaning/sterilisation, TG). Abutments were screwed in at 32 Ncm, provisional restorations adapted and periapical radiographs were taken using customised film holders. Two weeks later, definitive restorations were placed. Patients were followed-up for 2 years post-loading. Outcome measures were implant/crown success, complications, periapical marginal bone level changes on periapical standardised radiographs, and microbiological analyses of the abutments after customisation and cleaning procedures but before connection. Comparisons between groups were performed by independent sample t tests (significance threshold of P ≤ 0.05). Results: No patient dropped out 2 years after loading. The presence of bacterial growth (staphylococci, including Staphylococcus aureus) was observed only on the CG abutments. No implant failed and no complications occurred. After 2 years of prosthetic loading, radiographic analysis revealed a statistically significantly higher mean bone loss for the CG group (mean difference 0.4 mm; 95% CI 0.08-0.73; P = 0.018). Conclusions: This study suggests that removal of contaminants from titanium abutments using plasma of argon can allow for better bone level maintenance when compared to 5-second steam cleaning of titanium abutments. It is therefore important to use cleaned and sterilised customised abutments in patients. Keywords: glow-discharged, peri-implant bone level changes, plasma of Argon, prosthetic component cleaning, sterility, titanium abutment

Purpose: To assess the clinical 3-year outcome of prostheses supported by four immediately loaded zygomatic implants. Materials and methods: A total of 17 consecutively treated patients (7 men, 10 women, mean age 57.7 years) with severe maxillary atrophy were immediately rehabilitated with prostheses supported by four immediately loaded zygomatic implants. The patients were followed up for 3 years and the outcome measures included success rates of the prostheses, success rates of the zygomatic implants, complications and oral-health related quality of life (OHRQoL). Results: No patients dropped out. No prosthesis or zygomatic implants failed, though one implant was not used to support the final prosthesis because it emerged in an unfavourable position. Seven complications occurred: penetration of the orbital cavity during the drilling procedure with no relevant consequences; an infection followed by a fistula at one zygomatic implant, which was resolved with antibiotic treatment and surgical drainage; two patients developed sinusitis, and were successfully treated with antibiotics and meatotomy; fracture of the abutment screw occurred in one patient; and fracture of the prosthesis occurred in two patients and the definitive prostheses were repaired. The average score for the OHIP-14 questionnaire was 2.7, which was similar to that of the general population. Conclusions: The present 3-year study suggests that prostheses supported by four immediately loaded zygomatic implants can be used for successful rehabilitation of patients with severely atrophic maxillae. Keywords: alveolar bone loss/rehabilitation, dental implants, edentulous/rehabilitation, prospect ive studies, zygoma/surgery

Purpose: To report the outcome of trans-sinus tilted implants for the rehabilitation of the complete edentulous atrophic maxilla using the All-on-4 concept with immediate loading. Materials and methods: This retrospective clinical study included 70 patients treated with 280 implants (Nobel Biocare), 83 of which were trans-sinus implants supporting 70 prostheses. The inclusion criteria were need of maxillary complete edentulous rehabilitation without enough bone height posterior to the canines to anchor the implants. The trans-sinus implant head was anchored on the bone available just posterior to the anterior sinus wall and inferior to the sinus floor. The trans-sinus implant body was inside the sinus, and its apex anchored in the bone between the anterior sinus wall and the nasal cortical. The nasal cortical was used, if necessary, to achieve a double bicortical anchorage. Implants were immediately loaded with cross-arch fixed prostheses. Follow-up examinations were performed after 10 days, 2, 4 and 6 months, and 1, 2 and 3 years. Radiographic evaluations were performed after 1 and 3 years of function. Outcome measures were success of the prostheses, success of the implants, complications, peri-implant marginal bone levels, and aesthetic and functional complaints. Survival was calculated at implant level and using the patient as the unit of analysis (first implant failure in any given patient) using life-table analysis. Results: Seven patients dropped out of the study. Three trans-sinus tilted implants were lost in 3 patients, giving a cumulative survival rate of 95.7% and 96.4% at patient and implant level, respectively. One conventional tilted implant was lost in 1 patient (one of the patients that lost a trans-sinus tilted implant), giving a cumulative survival rate of 98.1%. One straight implant was lost in one patient (a second patient that lost a trans-sinus implant), giving a cumulative survival rate of 98.6% and 99.3% at patient and implant level, respectively. The survival rate of prostheses was 100%. Sinusitis occurred in 2 patients (2.9%). The marginal bone resorption was on average (standard deviation) 0.96 mm (0.62 mm) and 1.14 mm (0.74 mm) for the trans-sinus tilted implants, 0.89 mm (0.54 mm) and 1.06 mm (0.71 mm) for the conventional tilted implants, and 0.62 mm (0.35 mm) and 1.15 mm (0.51 mm) for the straight implants after 1 and 3 years of follow-up, respectively. Conclusions: The high survival rate registered at patient and implant level indicates that the outcome of immediately loaded trans-sinus implants for the rehabilitation of edentulous atrophic maxillae to avoid sinus lift procedures is a viable treatment in the short and medium term. Future studies should focus on the long-term outcome of this rehabilitation modality. Keywords: All-on-4, atrophic maxillae, complete edentulism, dental implants, trans-sinus

Purpose: The purpose of the study was to compare the clinical and aesthetic outcome of single postextractive 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. Keywords: delayed implants, immediate loading, post-extractive, single-tooth replacement