International Journal of Oral Implantology, 02/2019

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. Keywords: full arch prosthesis, immediate loading, maxillary atrophy, tilted implants, trans-sinus implant Conflict of interest statement: Tommaso Grandi and Rawad Samarani 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.

Purpose: To evaluate whether there are some clinical benefits by placing single dental implants either 0.5 mm or 1.5 mm subcrestally in healed bone crests. Materials and methods: Sixty partially edentulous patients requiring two single implant-supported crowns had both sites randomly allocated either to 0.5-mm or 1.5-mm subcrestal implant placement according to a split-mouth design at six centres and submerged in aesthetic areas or non-submerged in non-aesthetic areas for 3 months. Provisional acrylic crowns were delivered and were replaced after 2 months by definitive metal-ceramic crowns. Patients were followed to 3 years after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink aesthetic score (PES), peri-implant marginal bone level changes and patient preference, recorded by blinded assessors. Results: One patient dropped out. One patient lost both implants for infection at impression taking. Seven complications affected seven patients of the 0.5-mm group and four complications affected four patients of the 1.5-mm subcrestal group. Three patients had complications at both implants. There were no statistically significant differences for complications between group (OR = 4; 95% CI: 0.45 to 35.79; P (McNemar test) = 0.375). At delivery of definitive crowns, 2 months after loading, the mean PES was 11.22 ± 1.91 and 11.12 ± 1.59 for the 0.5- and 1.5-mm groups, respectively. At 1 year after loading, the mean PES was 12.09 ± 1.66 and 12.10 ± 1.52 for the 0.5- and 1.5-mm groups, respectively. At 3 years after loading, the mean PES was 11.99 ± 1.94 and 12.19 ± 1.78 for the 0.5- and 1.5-mm groups, respectively. There were no statistically significant differences between the two groups at 2 months (P = 0.626), at 1 year (P = 0.920) or at 3 years (P = 0.296). One year after loading, patients of the 0.5-mm group lost on average 0.21 ± 0.51 mm and those of the 1.5-mm group 0.11 ± 0.36 mm, the difference being not statistically significant (difference = 0.10 mm; 95% CI: −0.01 to 0.20; P = 0.078). Three years after loading, patients of the 0.5-mm group lost on average 0.34 ± 0.87 mm and those of the 1.5-mm group 0.19 ± 0.54 mm, the difference being statistically significant (difference = 0.15 mm; 95% CI: 0.00 to 0.30; P = 0.046). Patients did not prefer any depth of the implant placement over the other. There were no differences in outcomes between centres. Conclusions: No appreciable clinical differences were noticed when placing implants 0.5 mm or 1.5 mm subcrestally; therefore clinicians can do as they prefer. Keywords: aesthetics, bone level, dental implant, subcrestal placement Conflict of interest statement: Anthogyr (Sallanches, France), the manufacturer of the implants used in this investigation, partially funded this trial and donated the implants and the prosthetic components; however, data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.

Purpose: To evaluate if a different morphology of the implant-abutment connection (internal vs. external hexagon) is able to condition the behaviour of hard and soft peri-implant tissues. Materials and methods: Twenty patients with significantly unfavourable prognoses for their residual maxillary or mandibular dentitions were selected and rehabilitated with immediately loaded fixed full-arch rehabilitations in two different centres. Four to six implants with identical macro- and micro-topography were inserted in each arch: external hexagon implants (EHC) in one randomly selected side of the dental arch and internal hexagon implants (IHC) in the other side. Primary outcome measures were the success rates of the implants and prostheses. Any technical and biological complication was recorded. Secondary outcome measures were: peri-implant marginal bone level (MBL) changes, Plaque Index (PI), probing depth (PD) and bleeding on probing (BoP), evaluated at implant insertion and at 3, 6 and 12 months post-loading. Results: Forty-three EHC and 40 IHC implants were inserted in 20 patients. No patients dropped out. Two implants failed; one IHC after 3 months and one EHC after 6 months in two different patients (difference IHC vs. EHC at patient level: 0.06%; 95% CI: −1.9 to 2.1; P = 0.99). No prosthesis failed. No biological complications were identified and three loose prosthetic abutment screws were identified in three different patients (two EHC and one IHC); difference at patient level IHC vs. EHC: 2.1% (95% CI: −0.8 to 5; P = 0.43). Overall marginal bone loss was not significantly different between the two treatment groups (EHC vs. IHC) at any time point. The mean difference of bone levels between EHC and IHC was 0.25 mm (95% CI: −0.18 to 0.69) at implant placement. Mean difference between IHC and EHC was −0.01 mm (95% CI: −0.34 to 0.36) at 3 months, 0.13 mm (95% CI: −0.48 to 0.22) at 6 months and 0.11 mm (95% CI: −0.45 to 0.25) at 12 months. All the implants showed good periodontal health at the 1-year-in-function visit, with no statistically significant differences between groups. At 12 months mean (± standard deviation) PI was 2 (± 1.5) for the EHC and 1.85 (± 1.58) for the IHC group (P = 0.57) with a mean difference between the two groups of 0.15 (95% CI: −0.56 to 0.85). Mean PD was 2.23 mm (± 0.52) for the EHC and 2.10 mm (± 0.39) for the IHC group (P = 0.39), with a mean difference between the two groups of 0.12 mm (95% CI: −0.08 to 0.33). At 12 months 41.4% of EHC and 43.6% of IHC implants presented no BoP (mean difference: −2.2%, 95% CI: −24.0 to 19.3; P = 0.51). No significant effect of centres over all outcomes was identified (P = 0.71 for MBL, P = 0.14 for PI, P = 0.14 for PD and P = 0.20 for BoP). Conclusions: On the basis of the present trial the two types of implant connections were clinically reliable. After 12 months in function, both implants provided good clinical outcomes, without statistically significant differences between the two groups. Keywords: dental implants, immediate loading, implant abutment connection Conflict of interest statement: The authors declare that this study was partly funded by Sweden & Martina.

Purpose: To evaluate whether there is a difference in aesthetic outcomes positioning immediate post-extractive implants in the natural position (where the tooth should have been in relation to adjacent teeth/implants) or approximately 3 mm more palatally. Materials and methods: Just after tooth extraction, 20 patients requiring one single immediate maxillary post-extractive implant, from second premolar to second premolar, were randomly allocated to receive either an implant positioned in the natural 'central' position where the tooth should have been (central group; 10 patients) or approximately 3 mm more palatally (palatal group; 10 patients) according to a parallel-group design at two different centres. When needed, sites were reconstructed and bone-to-implant gaps were filled with granules of anorganic bovine bone, covered by resorbable collagen barriers. Implants were left submerged for 4 months and rehabilitated with provisional crowns, replaced after 4 months by metal-ceramic definitive crowns. Patients were followed to 3 years after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink aesthetic score (PES), peri-implant marginal bone level changes and patient satisfaction, recorded by blinded assessors. Results: Three patients from each group dropped out up to 3 years after loading. One implant failed in each group (14%), the difference being not statistically significant (difference in proportion = 0.00; 95% CI: −0.39 to 0.39; P = 1.000). Two palatal group patients and one natural position patient had a complication each, the difference being not statistically significant (difference in proportion = 0.14; 95% CI: −0.28 to 0.52; P = 1.000). Three years after loading, the median PES was 12.5 (interquartile range [IQR] 5.0) for the central and 10.0 (IQR 10.0) for the palatal group, the difference being not statistically significant (median difference = −1.5; 95% CI: −10.0 to 5.0; P = 0.476). Three years after loading, patients of the central group lost 0.25 (IQR 0.40) mm of peri-implant marginal bone and those of the palatal group 0.20 (IQR 0.88) mm, the difference being not statistically significant (median difference = 0.15 mm; P [Mann-Whitney U test] = 0.486). Patients of both groups were equally satisfied at 3 years after loading for both function and aesthetics (both P = 0.699). Conclusions: These preliminary results suggest that positioning of immediate post-extractive implants 3 mm more palatally may not improve aesthetics; however, the sample size of the present study was very limited, thus larger trials are needed to confirm or reject the present findings. Conflict of interest statement: Mozo-Grau, Valladolid, Spain, the manufacturer of the implants used in this investigation, donated the implants and partially supported this trial; however, data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results. Keywords: delayed, immediate, post-extractive implants Conflict of interest statement: Mozo-Grau, Valladolid, Spain, the manufacturer of the implants used in this investigation, donated the implants and partially supported this trial; however, data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.

Purpose: To compare accuracy and complications of computer-assisted template-based implant placement using conventional impression and scan of a physical stone cast or intraoral scanning to rehabilitate partially edentulous patients. Materials and methods: Any partially edentulous patients with at least five residual teeth, requiring at least one implant to be planned on three-dimensional (3D) cone beam computed tomography (CBCT) scan according to a computer-assisted template-based protocol were enrolled. Patients were randomised according to a parallel-group design into two arms: intraoral digital impression (fully digital group) or conventional impression and scan model (conventional group). Implants were placed flapless or with a minimally invasive flap, and conventionally loaded after 5 months. Outcome measures were implant and prosthetic success, complications, accuracy and peri-implant marginal bone loss. Three deviation parameters (angular, horizontal and vertical) were defined to evaluate the discrepancy between the planned and placed implant positions. Results were compared using a mixed-model repeated-measures analysis of variance (α = 0.05). Results: Twenty patients (11 females and 9 males; mean age 44.6 years old) were randomised to the fully digital group (10 patients with 28 implants) or conventional group (10 patients with 29 implants). No patients dropped out. No implant or prosthesis failed up to 1 year after loading. One implant in the fully digital group was placed freehand due to limited inter-arch space. No biological or mechanical complications were experienced during follow-up. Difference between groups were not statistically significant (P = 0.999). The mean error in angle was 2.25 ± 1.41 degrees (range 0.30 to 5.00 degrees; 95% CI: 1.38 to 3.12 degrees) in the fully digital group and 2.10 ± 1.18 degrees (range 0.30 to 5.80 degrees; 95% CI: 1.37 to 2.83 degrees) in the conventional group. The difference was not statistically significant (−0.15 ± 1.63 degrees; range −3.20 to 2.90 degrees; 95% CI: −0.87 to 0.57 degrees; P = 0.668); in the horizontal plane (mesio-distal), the mean error was 0.52 ± 0.30 mm (range 0.10 to 1.10 mm; 95% CI: 0.33 to 0.70 mm) in the fully digital group and 0.44 ± 0.26 mm (range 0.10 to 0.90 mm; 95% CI: 0.27 to 0.60 mm) in the conventional group. The difference was not statistically significant (−0.08 ± 0.38 degrees; range −1.0 to 0.60 degrees; 95% CI: −0.32 to 0.16 degrees; P = 0.279); in the vertical plane (apico-coronal), the mean error was 0.58 ± 0.44 mm (range 0.00 to 1.60 mm; 95% CI: 0.31 to 0.85) in the fully digital group and 0.46 ± 0.34 mm (range 0.00 to 1.20 mm; 95% CI: 0.25 to 0.67) in the conventional group. The difference was not statistically significant (−0.12 ± 0.59 degrees; range −1.20 to 1.00 degrees; 95% CI: −0.49 to 0.24 degrees; P = 0.250). One year after loading, the mean marginal bone loss was 0.14 ± 0.12 mm (range −0.10 to 0.40 mm; 95% CI: 0.07 to 0.21 mm) in the fully digital group and 0.18 ± 0.13 mm (range −0.10 to 0.60 mm; 95% CI: 0.09 to 0.26 mm). The difference was not statistically significant (−0.04 ± 0.19 mm; range -0.50 to 0.30 mm; 95% CI: −0.16 to 0.08 mm; P = 0.294). Conclusions: With the limitations of the present trial, implant rehabilitations planned using intraoral digital impressions showed similar results compared to conventional impression and scan model. Digital impression may be a viable option for the rehabilitation of partial edentulous patients when computer-guided template-assisted implant placement is used. Keywords: accuracy, dental implants, digital impression, guided surgery, intraoral scanner Conflict of interest statement: Dr Marco Tallarico is a consultant for the Osstem Implant and New Ancorvis. Dr Fabio Cocchi is a consultant for New Ancorvis. However, this study was selfsupported. Data belonged to the authors and by no means did the companies interfere with the conduct of the trial or the publication of its results.

Purpose: To test a minimally invasive flap in the lateral approach for maxillary sinus floor elevation when compared to a trapezoidal flap. Materials and methods: Each patient received a bilateral sinus elevation procedure based on two different randomly allocated surgical approaches according to a split-mouth design: in the test side, a horizontal incision at mucogingival line was realised; in the control side, a trapezoidal flap was elevated to prepare the lateral window. Each sinus was filled using deproteinised bovine bone and the window covered with a collagen membrane. Implants were inserted according to a two-stage technique 6 months after sinus elevation procedures, submerged and then loaded after 6 months with definitive screw-retained metal-ceramic prostheses. Patients were followed up to 4 months post-loading. Outcome measures included: implant and prosthesis failures, complications, peri-implant marginal bone level changes, residual bone height and width, recorded before sinus augmentation and 180 days post-intervention by computed tomography (CT) scans, surgical times and patient discomfort data, assessed using a visual analogue scale (VAS) diagram for each treated side at 1, 7, 14 and 30 days of follow-up. Results: Seventeen patients were enrolled in this trial and none dropped out. Five completely edentulous patients were treated with full-arch prosthetic restorations (Toronto dental prosthesis) and 12 patients with partial metal-ceramic screw-retained prostheses. In total 72 implants were inserted, 37 in the test group and 35 in the control group. No prosthesis or implant failures occurred. A total of seven patients showed complications: five of them had complications in both test and control sides. Eight complications were detected in each group. During maxillary sinus elevation procedures, nine interventions (four from the test group and five from the control group) were affected by intrasurgical complications (six membrane perforations and three severe bleedings); post-surgical complications occurred to three patients (one submucosal emphysema in a patient from the test group, one wound dehiscence and a graft infection both recorded in the control group); a total of four implants in two patients in the test group, versus three implants from one patient in the control group showed peri-implant mucositis. There were no statistically significant differences in complications between the two groups (P = 1.00; 95% confidence interval [CI]: 0.15-3.11). Patients from the control group, at 4 months after loading, lost on average 0.53 mm (standard deviation [SD] 0.27; 95% CI: 0.40-0.65), and patients from the test group lost on average 0.66 mm (SD 0.27; 95% CI: 0.53-0.78); the difference was not statistically significant (mean difference: 0.07 mm; SD 0.34; 95% CI: −0.03-0.17; P = 0.102). Significant values for bone augmentation in height, 9.26 mm (SD 1.46; 95% CI: 8.56-9.95) in the test group and 9.38 mm (SD 1.95; 95% CI: 8.45-10.30) in the control group, and width, 1.68 mm (SD 1.04; 95% CI: 1.18-2.20) in the test group and 1.60 mm (SD 1.27; 95% CI: 0.99-2.20) in the control group, were found from the 180-day CT scans. No statistically significant differences were detected between the two groups, either for the bone augmentation data (difference: 0.27 mm; 95% CI: 0.15-0.38; P = 0.60) or for the bone width values (difference: 0.02 mm; 95% CI: 0.07-0.11; P = 0.67). A significant reduction in the total surgical time was found in the test group (mean difference: 6.64 minutes; SD 4.32; 95% CI: 4.58-8.69), with the difference being statistically significant (P = 0.009). Evaluation of patients' postoperative discomfort showed a significant preference for the test procedure: at 1 day the VAS value was 4 (interquartile range [IQR] 2 to 5) in the test group; in the control group the VAS score was 5 (IQR 4 to 8). The intergroup difference was statistically significant (P = 0.002). At the 7-day follow-up, the VAS value was 1 in the test group (IQR 0 to 3) and 3 in the control group (IQR 0 to 7), this difference was statistically significant (P = 0.003). No differences were detected at 14 and 30 days (P > 0.05). Conclusions: A minimally invasive approach to access the sinus cavity can be as successful as a conventional trapezoidal flap in maxillary sinus floor elevations. Keywords: patient-centred outcome, sinus elevation, surgical procedure, wound healing Conflict of interest statement: The authors declare that they have no conflicts of interest; they do not have any financial interest in products cited in the manuscript. The authors were fully independent in preparing the protocol, conducting the research, interpreting the results and preparing the manuscript.

Purpose: To evaluate possible risk factors associated with wound dehiscences following pre-implant alveolar bone augmentation with autologous anterior iliac crest bone grafts covered with resorbable collagen membranes or human demineralised bone laminae. Materials and methods: Data of 161 patients who underwent bone augmentation prior to the insertion of dental implants were analysed. The preoperative dental status, locations of alveolar bone augmentation sites and location of wound dehiscences were recorded. Gender, age, smoking, alcohol exposure, and dental and medical histories were reviewed. Information was also collected on the surgeons, augmentation technique, application of a collagen membrane, fixation screw type and suture material. Univariate logistic regression analysis was used to evaluate pre- and perioperative variables as predictors of dehiscences. Results: A total of 42 (26.1%) of the 161 augmented patients developed a wound dehiscence following surgery. Most commonly affected sites were the anterior maxilla, followed by the anterior mandible. Males developed wound dehiscences with higher probability than females (odds ratio female = 0.444; P = 0.025; 95% CI: 0.214 to 0.903). Furthermore, marginal associations (P < 0.10) are found for smoking and an anterior location of the augmentation. Smokers were found to have higher probability of a wound dehiscence (odds ratio 2.089; P = 0.064; 95% CI: 0.957 to 4.500) compared to non-smokers. A posterior location of the augmentation was associated with lower probability of a wound dehiscence (odds ratio 0.188; P = 0.076; 95% CI: 0.035 to 0.802) compared to an anterior location. Conclusions: Based on this study population, smoking in males seems to be the most important risk factor for the development of wound dehiscences after pre-implant alveolar bone augmentation procedures. Keywords: autologous iliac crest bone graft, bone augmentation, bone graft, dental implants, failure analysis, surgical procedure, wound dehiscence Conflict of interest statement: The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

This section presents a brief review of articles on dental implants considered of special interest to the reader, in order to encourage the development of research, data analysis and scientific publication. Your comments are welcome. Please contact Dr Michele Nieri at michelenieri@gmail.com.