International Journal of Oral Implantology, 03/2012

This review is based on a Cochrane systematic review entitled 'Interventions for replacing missing teeth: management of soft tissues for dental implants' published in The Cochrane Library (see http:// www.cochrane.org/ for information). Cochrane systematic reviews are regularly updated to include new research, and in response to comments and criticisms from readers. If you wish to comment on this review, please send your comments to the Cochrane website or to Marco Esposito. The Cochrane Library should be consulted for the most recent version of the review. The results of a Cochrane review can be interpreted differently, depending on people's perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by the Cochrane Collaboration. Purpose: To evaluate whether flapless procedures are beneficial for patients and which is the ideal flap design, whether soft tissue correction/augmentation techniques are beneficial for patients and which are the best techniques, whether techniques to increase the peri-implant keratinised mucosa are beneficial for patients and which are the best techniques, and which are the best suturing techniques/ materials. Materials and methods: The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched up to the 9th of June 2011 for randomised controlled trials (RCTs) of rootform osseointegrated dental implants, with a follow-up of at least 6 months after function, comparing various techniques to handle soft tissues in relation to dental implants. Primary outcome measures were prosthetic failures, implant failures and biological complications. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted at least in duplicate and independently by two or more review authors. The statistical unit was the patient and not the prosthesis, the procedure or the implant. Results were expressed using risk ratios for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals (CI). Results: Seventeen potentially eligible RCTs were identified but only six trials with 138 patients in total could be included. The following techniques were compared in the six included studies: flapless placement of dental implants versus conventional flap elevation (2 trials, 56 patients), crestal versus vestibular incisions (1 trial, 10 patients), Erbium:YAG laser versus flap elevation at the second-stage surgery for implant exposure (1 trial, 20 patients), whether a connective tissue graft at implant placement could be effective in augmenting peri-implant tissues (1 split-mouth trial, 10 patients), and autograft versus an animal-derived collagen matrix to increase the height of the keratinised mucosa (1 trial, 40 patients). On a patient rather than per implant basis, implants placed with a flapless technique and implant exposures performed with laser lead to statistically significantly less postoperative pain than flap elevation. Sites augmented with soft tissue connective grafts had better aesthetics and thicker tissues. Both palatal autografts or the use of a porcine-derived collagen matrix are effective in increasing the height of keratinised mucosa at the cost of a 0.5 mm recession of peri-implant soft tissues. There were no other statistically significant differences for any of the remaining analyses. Conclusions: There is limited weak evidence suggesting that flapless implant placement is feasible and has been shown to reduce patient postoperative discomfort in adequately selected patients, that augmentation at implant sites with soft tissue grafts is effective in increasing soft tissue thickness and improving aesthetics, and that one technique to increase the height of keratinised mucosa using autografts or an animal-derived collagen matrix was able to achieve its goal but at the cost of a worsened aesthetic outcome (0.5 mm of recession). There is insufficient reliable evidence to provide recommendations on which is the ideal flap design, the best soft tissue augmentation technique, whether techniques to increase the width of keratinised/attached mucosa are beneficial to patients or not, and which are the best incision/suture techniques/materials. Properly designed and conducted RCTs, with at least 6 months of follow-up, are needed to provide reliable answers to these questions. Keywords: dental implant, flap, keratinised mucosa, randomised controlled clinical trial, soft tissue augmentation, suture, systematic review

Purpose: To evaluate clinical safety and effectiveness of a novel calcium-incorporated titanium implant (Xpeed, MegaGen Implant Co. Limited, Gyeongbuk, South Korea). Materials and methods: Sixty patients were randomised to receive either 1 to 6 calcium-incorporated or control titanium implants in the maxilla according to a parallel group design at 2 different centres. Implants were submerged and exposed at 3 different endpoints in equal groups of 20 patients each at 12, 10 and 8 weeks, respectively. Within 2 weeks, implants were functionally loaded with provisional or definitive prostheses. Outcome measures were prosthesis failures, implant failures, any complications and peri-implant marginal bone level changes. Results: Thirty patients received 45 calcium-incorporated implants and 30 patients received 42 control titanium implants. One year after loading, no drop-outs and no prosthesis or implant failures occurred. There were no statistically significant differences between groups for complications (P = 0.61; difference in proportions = -0.27; 95% CI -0.71 to 0.18) and mean marginal bone level changes (P = 0.64; mean difference -0.04 mm; 95% CI -0.22 to 0.13). Conclusions: Nanostructured calcium-incorporated titanium implants seem to be at least as effective and safe as conventional titanium implants. Keywords: calcium-incorporated titanium, early loading, randomised controlled trial, surface modification

Purpose: To evaluate whether platform switching could preserve marginal bone around implants up to 6 months after loading. Materials and methods: 15 patients were selected for a randomised controlled trial. Each patient received one customised wide body implant, with the external hex connection located eccentrically, allowing an extra 1 mm switch on one side. The hex was positioned at random at the mesial or distal side and the implant was loaded after 6 months of non-submerged healing. Patients were examined at 3, 6 and 12 months after surgery, during which a radiograph was taken to evaluate bone levels. At 12 months, the mucosal thickness was measured using a perio-probe. Results: All implants survived and the mean overall bone loss, calculated from both the switched and non-switched side, was 0.39 mm (SD 0.33, range 0.00-1.45), 0.85 mm (SD 0.59, range 0.10-2.50) and 0.80 mm (SD 0.46, 0.26-1.89) after 3, 6 and 12 months, respectively. The bone loss continued up to 6 months but stabilised thereafter (P = 0.615). Significantly more bone loss was observed at the non-switched side compared to the switched side at 3 months (0.51 mm versus 0.28 mm, P = 0.019), 6 months (1.05 mm versus 0.64 mm, P = 0.002) and 12 months (0.94 mm versus 0.66 mm, P = 0.002). The mean mucosal thickness was 4.22 mm (SD 1.45; range 1.50-7.00), and was not significantly different between the switched and non-switched sides (P = 0.882). However, using a post-hoc analysis with the mean thickness as a threshold, the mean bone loss was only significantly different between switched and non-switched sides when the mucosa was thicker than 4.22 mm (P = 0.036). Conclusions: The outcome of this randomised trial is in accordance with earlier studies suggesting that that platform switching decreases bone loss by 30%. Although the sample size was limited, it seems that the creation of a biologic width affects peri-implant bone loss to a significant extent and that platform switching is only effective when the mucosal thickness allows the establishment of a biologic width. Keywords: bone loss, implant, platform switching, southern implants, wide body

Purpose: The aim of this ongoing prospective study was to determine the 5-year survival rate of short porous dental implants in the posterior atrophic maxilla combined, when necessary, with crestal sinus floor elevation and often adding anorganic bovine bone. Materials and methods: In 87 partially edentulous patients, 110 short porous implants were placed and followed up for 5 years. The implants used were of two lengths (5 and 7 mm) and two diameters (4.1 and 5 mm) and were chosen according to the available crestal height and width. In 47 sites, osteotome sinus floor elevation was performed (in 8 cases compacting basal bone, in 39 adding a xenograft). The unloaded healing period was 6 months. A total of 63 implants were restored with single crowns and 47 were splinted to the adjacent implants. Outcome measures were prosthesis and implant failures, any complications, and peri-implant marginal bone resorption. Results: Five years after loading, no patients dropped out. Eleven implants failed: 2 implants at uncovering and 9 after prosthetic loading. Eleven patients (12.6%) lost 1 implant. In 6 patients (6.9%) a prosthesis failure occurred (implants loaded with single crowns). One surgical complication (membrane perforation) occurred but the implant was normally inserted. No complications occurred during the healing period. In 3 patients, severe peri-implantitis occurred post loading and the implants had to be removed. Two abutments became loose and one crown chipped. At the end of the follow-up period the implant survival rate was 90%, and 93.1% with regard to prosthetic reconstruction. The mean peri-implant marginal bone loss was 1.4 mm. Conclusions: The use of short porous implants showed an acceptable clinical outcome in the treatment of the posterior maxilla in this interim 5-year report. Longer follow-ups are needed to confirm these results. Keywords: deproteinised bovine bone, implant prosthesis, osteotome sinus elevation, posterior maxilla, short dental implants

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. Keywords: full-arch prosthesis, immediate loading, post-extractive implants, tilted implants

Aim: To present a rare but clinically significant complication to sinus floor elevation (SFE) using the transcrestal technique. Materials and methods: Transcrestal SFE with simultaneous implant placement was performed in the maxillary right second premolar region of a healthy 70-year-old woman with no history of a bleeding disorder. Results: The patient reported to the emergency care unit a few hours after the surgery with ongoing bleeding and progressive swelling of especially the right side of the midface. The buccal swelling did not allow the patient to close her mouth and the discoloration extended to the sternum. A computed tomography scan showed pronounced swelling of the facial soft tissue and the right sinus cavity completely filled with blood. The patient was kept hospitalised for 3 days until regression of the swelling was attained and acceptable oral function was regained. Conclusion: Transcrestal SFE is often recommended to the less experienced surgeon before the lateral window technique due to fewer complications and lower morbidity. The present case illustrates that severe complications may accompany transcrestal SFE. Although rare, clinicians performing SFE should be aware of this potential risk. Keywords: complication, dental implants, haemorrhage, sinus floor elevation, vascularisation