Walther Wegscheider

Three-Dimensional Accuracy of Guided Implant Placement: Indirect Assessment of Clinical Outcomes

PURPOSE Precise preoperative implant planning and its exact intraoperative transfer are crucial for successful implant-supported rehabilitation of partially or completely edentulous patients. In the present pilot study, optical laser scanning was used to evaluate deviations between three-dimensional computer-assisted planned and actual implant positions by indirect methods. MATERIAL AND METHODS Five patients receiving a total of 15 implants were included in this study. The used planning software was SimPlant 12.0 (Materialise Dental, Leuven, Belgium) to visualize the implant positions, and with an appropriate guided surgery protocol (Navigator™, Biomet 3i, Palm Beach Gardens, FL, USA) implant positions were implemented via tooth-supported stereolithografic surgical guides. All implants (Osseotite™, Biomet 3i) were inserted in a flapless approach and immediately provided with prefabricated temporary splinted restorations. Intraoral pickup impressions were taken postoperatively, and the implant positions of the master casts were compared with presurgical casts. Implant replica deviations were evaluated by three-dimensional optical laser scanning providing distances and angulations between implant replicas. RESULTS Overall, the postsurgical implant replica positions were found to deviate from the positions in the preoperative cast by a mean of 0.46 ± 0.21 mm (range: 0.09-0.85 mm). Positional deviations were 0.27 ± 0.19 mm (range: 0.04-0.60 mm) along the x-axis representing the buccal-lingual directions, 0.15 ± 0.13 mm (range: 0.0-0.34 mm) along the y-axis representing the ventrodorsal direction, and 0.28 ± 0.19 mm (range: 0.02-0.59 mm) along the z-axis representing cranial and apical directions. Rotational deviations amounted to 14.04 ± 11.6° (range: 0.09-36.47°). CONCLUSIONS The results of this pilot study demonstrate precise transfer of implant replica position by means of simulated guided implant insertion into a preoperative cast and a postoperative cast obtained from impressioning. Further studies are needed to identify appropriate evaluation techniques and mechanisms to increase the transfer precision of three-dimensional planning and guiding systems.

Soft tissue development around abutments with a circular macro-groove in healed sites of partially edentulous posterior maxillae and mandibles: a clinical pilot study.

OBJECTIVES The aim of this study was to evaluate soft tissue development at concave circular macro-grooved titanium abutments in healed sites. MATERIAL AND METHODS In a split-mouth pilot study 10 patients received two implants each at healed posterior sites in contralateral maxillary or mandibular jaw quadrants. Either circular macro-grooved concave study abutments or conventional convex control abutments were immediately provisionalized and received permanent crowns 3 months postimplantation. Marginal bone level, papilla index, modified plaque and bleeding index were recorded. The esthetic outcome was evaluated with standardized perpendicular pictures according to the Pink Esthetic Score (PES). Statistical analysis included the description of all variables by mean value, standard deviation and range. PES values were compared using the Wilcoxon signed rank test for paired data. RESULTS Cumulative survival rate for all 20 implants was 100%. At the 1-year follow-up, there was no statistical significant difference of marginal bone levels between sites restored with the study (-0.11 ± 0.77 mm) vs. the control (-0.34 ± 0.53 mm) abutments (P>0.05). Esthetic evaluation (PES) revealed statistically significant differences in scores between the study group [study abutment group] (7.2 ± 2.82, 8 ± 1.89) and the control group [control abutment group] (9.5 ± 1.58, 10.5 ± 1.72) at the time of prosthetic delivery and the 1-year follow-up. Whereas PES scores for mesial papilla at control sites at the 1-year follow-up demonstrated statistically significant higher values, both soft tissue level and soft tissue contour at control sites revealed statistically significantly higher PES values (P<0.05) at time of prosthetic delivery and at 1-year follow-up when compared with study sites. CONCLUSIONS Concave macro-grooved abutments in healed posterior maxillary and mandibular sites did not exhibit a superior soft tissue development compared with standard convex abutments.

Immediate provisional restoration of screw-type implants in the posterior mandible: results after 5 years of clinical function.

OBJECTIVE The aim of this prospective study was to evaluate the outcome of immediately provisionally restored implants in the posterior mandible after a minimum of 60 months in function. MATERIAL AND METHODS Twenty-four patients were treated with 40 screw-type implants replacing mandibular molars and premolars. Implants were provisionalized immediately after placement. Radiographic coronal bone levels, implant survival and success were evaluated 12, 24, 36, 48 and 60 months after the final restoration. RESULTS Measurements of the mean marginal bone levels around immediately loaded implants after 12 months showed a significant bone loss (P<0.001) within the first year after the final restoration. Measurements of coronal bone levels after 24, 36, 48 and 60 months, respectively, showed no further significant increase of bone resorption. Two implants were lost within the first year after the final restoration, resulting in an overall survival rate of 95%; a total of three implants were recorded as failures (two implant losses and one excessive bone resorption above 50%), resulting in an overall success rate of 92.5 after an implant observation period of up to 8 years. CONCLUSION The present data revealed results comparable to conventionally loaded implants. Careful patient selection in combination with high primary stability seem to be key factors for immediately loaded implants. Larger long-term randomized clinical trials are needed to confirm the final evidence of this protocol as the standard treatment concept for the partially edentulous mandible.

Oral Rehabilitation of Adult Twins With Severe Lack of Bone Due to Hypohidrotic Ectodermal Dysplasia : A 12-Month Follow-Up

PURPOSE Patients with x-linked hypohidrotic ectodermal dysplasia (XLHED, OMIM 305100) often present with exceptional oral conditions, because alveolar ridges can remain severely hypotrophic due to oligo- or anodontia in the primary and/or permanent dentition. This can seriously disable a young person physically and psychologically, and lead to sociopsychological isolation. PATIENTS AND METHODS The oral rehabilitation of fraternal male twins with XLHED, one with severe hypodontia and the other with anodontia is described. The treatment of both patients comprised augmentation of the jaws using bicortical corticocancellous bone blocks from the medial aspect of the anterior hip, delayed implantation, and restoration of the occlusion with bar-retained overdentures. The multidisciplinary team approach included an oral and maxillofacial surgeon, a prosthodontist, and a speech therapist. RESULTS After uneventful healing, the 12-month follow-up showed that sufficient osseointegration of the implants for optimized function was obtained by creating adequate de novo bone volume in the underdeveloped jaw regions. Full regular masticatory function was achieved, and esthetics were improved considerably in both patients. CONCLUSION Augmentation and implant placement prior to prosthetic rehabilitation appears to be a suitable treatment option for adult patients with XLHED.

Overdentures in the Edentulous Mandible Supported by Implants and Retained by a Dolder Bar: A 5‐Year Prospective Study

PURPOSE This prospective study was performed to evaluate the outcomes of XiVE® S plus implants (Dentsply Friadent, Mannheim, Germany) following conventional restoration with bar structures and overdentures in the edentulous mandible. MATERIALS AND METHODS A total of 39 patients were treated with four interforaminal implants (n = 156) splinted by a Dolder bar. Overdentures were attached to the bars after 3 months of healing. As primary outcome measures, clinical and radiological parameters were evaluated at the time of implant placement (baseline) and once a year (1, 2, 3, 4, 5 years) after functional loading. Secondary outcome measures included (i) primary stability and surgical complications, as well as (ii) Periotest® (Medizintechnik Gulden, Modautal, Germany) values, implant survival, and prosthetic complications at baseline and follow-up. RESULTS A total of 156 implants were placed. The vast majority (n = 149) were tightened to >30 Ncm, while torques in the range of 20-30 Ncm were obtained in the remaining cases (n = 7). Mean crestal bone levels around the implants were 0.41 mm at baseline and 1.04/1.20/1.34/1.45/1.44 mm after 1/2/3/4/5 years respectively. The mean values of the plaque, calculus, bleeding, and mucosal indices remained low throughout this period. The reported follow-up periods involved one implant loss after 3 months (survival rate: 99.4%) and one implant failure after 4 years (success rate: 98.4%). Prosthetic complications included factures of bars (n = 3) and denture teeth (n = 7). Prosthetic survival was 100%. CONCLUSIONS Dolder bars to restore oral implants in the edentulous mandible appear to offer a high rate of implant survival, good stability of the peri-implant tissue, and a low rate of prosthetic complications.

Immediate Occlusal versus Non‐Occlusal Loading of Implants: A Randomized Clinical Pilot Study

BACKGROUND Immediate occlusal and non-occlusal loading protocols have been discussed and, despite varying success rates, are considered viable in selected cases. Preoperative implant planning and intraoperative transfer are essential to the success of implant-supported reconstructions in partially or completely edentulous jaws. PURPOSE This study was performed to compare clinical outcomes of immediate occlusal versus non-occlusal loading of posterior implants. MATERIALS AND METHODS Of 19 patients with 52 screw-type implants replacing mandibular molars or premolars, nine patients with 21 implants were randomized to a study group that received immediate restorations with occlusal loading, whereas 10 patients with 31 implants were randomized to a control group that received provisional restorations without occlusal loading. Occlusal loading was defined as full loading in maximum intercuspidation. Single-tooth or splinted multiunit restorations were incorporated by screw retention or cementation. Marginal bone defects (MBD), implant survival, and implant success were evaluated 12 months after insertion. RESULTS Both groups revealed similar MBD levels consistent with previous reports. No implants were lost (overall survival: 100%) or found to fail (overall success: 100%). No significant intergroup differences were noted for any of the evaluated parameters. CONCLUSIONS Immediate restorations in partially edentulous mandibles demonstrated successful clinical and radiographic 12-month results. Larger long-term prospective studies are needed to confirm the final evidence and predictability of immediate functional loading as a standard treatment concept for partially edentulous jaws.

The system of prosthetic treatment for CLAP patients

The prosthetic treatment of CLAP patients is usually done in three phases: an interceptive treatment during two stages of orthodontics, the definitive prosthetic treatment and usually the secondary treatment. In the interceptive phase we use clasp-retained partials; the definitive treatment is achieved mostly by telescope-retained partials. There is seldom an indication for Maryland-bridges or for dental implants.

Immediate loading of four interforaminal implants supporting a locator-retained mandibular overdenture in the elderly. Results of a 3-year randomized, controlled, prospective clinical study

BACKGROUND Implant-retained overdentures have become a standard option for the prosthetic treatment of the edentulous mandible in the elderly. PURPOSE This prospective study aimed to compare immediate and conventional loading of four interforaminal implants supporting a Locator-retained mandibular overdenture in elderly patients regarding implant survival, implant stability, and implant-related complications. MATERIAL AND METHODS The study population comprised 20 completely edentulous patients (11 males) aged 60 years and older with severe mandible resorption. Each patient received four interforaminal implants (Neoss Ltd., Harrogate, UK). Following randomization, implants were loaded either immediately after dental implant surgery or 3 months after implant placement with the Locator-abutment system. At follow-up visits 3, 6 12, 24, and 36 months after loading, implant stability was evaluated with Periotest and Ostell. RESULTS Twenty patients received 80 implants. In eight patients, 32 implants were loaded immediately. Two patients had to be switched from the immediate to the conventional loading group due to insufficient primary stability (≤30 Ncm). Implant survival was similar in both groups after 36 months. No implant was lost. Decreasing Periotest, and accordingly, increasing Ostell measurements indicated adequate osseointegration in both groups. The course of treatment was not significantly different in the two groups. There were comparable incidences of postoperative complaints like swelling, hematoma, or wound dehiscence, as well as need for prosthetic treatment due to abutment loosening or occlusal discrepancies. Incidence of pressure marks and number of patient visits were significantly higher in the conventional loading group. CONCLUSION With sufficient primary stability, immediate loading of four interforaminal implants in the edentulous mandible might be the preferential choice in the elderly, reducing total treatment time, and number of patient visits.