Hans-Joachim Nickenig

Radiographic evaluation of marginal bone levels adjacent to parallel-screw cylinder machined-neck implants and rough-surfaced microthreaded implants using digitized panoramic radiographs.

OBJECTIVE The purpose of this split-mouth study was to compare macro- and microstructure implant surfaces at the marginal bone level during a stress-free healing period and under functional loading. MATERIAL AND METHODS From January to February 2006, 133 implants (70 rough-surfaced microthreaded implants and 63 machined-neck implants) were inserted in the mandible of 34 patients with Kennedy Class I residual dentitions and followed until February 2008. The marginal bone level was radiographically determined, using digitized panoramic radiographs, at four time points: at implant placement (baseline level), after the healing period, after 6 months of functional loading, and at the end of follow-up. RESULTS The median follow-up time was 1.9 (range: 1.9-2.1) years. The machined-neck group had a mean crestal bone loss of 0.5 mm (range: 0-2.3) after the healing period, 0.8 mm after 6 months (range: 0-2.4), and 1.1 mm (range: 0-3) at the end of follow-up. The rough-surfaced microthreaded implant group had a mean bone loss of 0.1 mm (range: -0.4-2) after the healing period, 0.4 mm (range: 0-2.1) after 6 months, and 0.5 mm (range: 0-2.1) at the end of follow-up. The two implant types showed significant differences in marginal bone levels (healing period: P=0.01; end of follow-up: P<0.01). CONCLUSIONS Radiographic evaluation of marginal bone levels adjacent to machined-neck or rough-surfaced microthreaded implants showed that implants with the microthreaded design caused minimal changes in crestal bone levels during healing (stress-free) and under functional loading.

Evaluation of the difference in accuracy between implant placement by virtual planning data and surgical guide templates versus the conventional free-hand method – a combined in vivo – in vitro technique using cone-beam CT (Part II)

PURPOSE The purpose of this study was to assess the accuracy of implant placement after virtual planning of implant positions using cone-beam CT data and surgical guide templates, and to match the results with those achieved with the conventional free-hand method. MATERIALS AND METHODS Twenty-three implants were placed in 10 patients with a Kennedy Class II with 3-dimensional (3-D) planned surgical guide template. Manual implantation was performed in anatomical casts of the same patients by a prosthodontist and a maxillofacial surgeon. Postoperative images of casts were superimposed onto the preoperative image of virtual planned ideal position of the implant. RESULTS The 3-D surgical guide template produced significantly smaller variation between the planned and actual implant positions at the implant shoulder (0.9 mm (0-4.5)) and apex (0.6-0.9 mm (0.0-3.4)) compared with the free-hand implantation (2.4-3.5 mm (0.0-7.0); p=0.000 and 2.0-2.5 mm (0.0-7.7); p=0.002). Accuracy of axis was also significantly improved. CONCLUSIONS Accuracy of implant placement after virtual planning of implant position using cone-beam CT data and surgical templates is high and significantly more accurate than free-hand insertion. The demonstrated method of superimposing radiographic images of postoperative casts and virtual planning images is a useful method, which allows reduced patient radiation exposure.

An alternative method to match planned and achieved positions of implants, after virtual planning using cone-beam CT data and surgical guide templates – A method reducing patient radiation exposure (part I)

OBJECTIVES The present study describes a new method of evaluating the precision of surgically placed dental implants compared after virtual planning of implant positions using cone-beam computed tomography (CT) data and surgical guide templates. This method reduces radiation exposure for patients participating in scientific studies. MATERIALS AND METHODS Twenty-three implants in 10 patients with a unilateral free-end gap in the mandible (Kennedy Class II) were evaluated. After three-dimensional planning of implant position, the implant bed was prepared with a surgical guide template and transmucosal drilling. Preoperative cone-beam CT images were matched with postoperative images of the master cast with implant replicas. Deviations between planned and achieved positions were measured in position and axis. RESULTS On average, the match between planned and placed implant axis was within 4.2 degrees (range, 0.0-10.0). The mean difference in distance at the implant shoulder was 0.9 mm (range, 0.0-4.5). The mean difference in distance at the implant apex was 0.6mm (range, 0.0-2.7) in the lateral/medial direction and 0.9 mm (range, 0.0-3.4) in the anterior/posterior direction. CONCLUSIONS This alternative matching method provides reliable postoperative evaluation of differences in position and axis of planned and placed implants while reducing patient radiation exposure.

Radiographic evaluation of marginal bone levels during healing period, adjacent to parallel‐screw cylinder implants inserted in the posterior zone of the jaws, placed with flapless surgery

OBJECTIVE The purpose of this study was to compare changes at the marginal bone level adjacent to implants placed with flapless surgery and flap surgery during a stress-free healing period. MATERIAL AND METHODS Seven hundred and eighty-five implants were placed in 417 patients with a flapless approach and 459 implants were placed in 227 patients using flap techniques. The marginal bone level was determined radiographically, using digitized panoramic radiographs, at two time points: at implant placement (baseline) and after the healing period. RESULTS The median follow-up time was 0.5 years (SD, 1.2; range: 0.3-0.7). Implants placed with flapless surgery had a mean crestal bone loss of 0.5 mm (SD, 0.5; range: -0.7-2.4) and implants placed with flap surgery had a mean bone loss of 0.5 mm (SD, 0.7; range: -2.0-3.0) after healing. Differences in bone level changes between smokers and non-smokers were statistically significant for the flapless group (P<0.01). CONCLUSIONS A radiographic evaluation of marginal bone levels adjacent to implants showed comparable results for implants placed with flapless surgery and flap surgery. Appropriate case selection after virtual planning of the implant position and a sound surgical protocol is necessary for flapless surgery. Smoking habits may compromise the efficacy of flapless implant procedures.

Comparison of Conventional Therapies for Dentin Hypersensitivity Versus Medical Hypnosis

Abstract This study compared the efficacy of conventional treatments for dentin hypersensitivity (DHS) and hypnotherapy. During a 1-month period at an urban practice in a service area of approximately 22,000 inhabitants, all patients were examined. A total of 102 individuals were included in the evaluation. Values of 186 teeth were analyzed. The comparison of the different treatment methods (desensitizer, fluoridation, and hypnotherapy) did not show significant differences in success rates. However, a noticeable difference was observed in terms of onset and duration of effect. For both desensitizer and hypnotherapy treatments, onset of effect was very rapid. Compared to the other methods studied, hypnotherapy effects had the longest duration. In conclusion, hypnotherapy was as effective as other methods in the treatment of DHS.

Sarcomas of the sinonasal tract

Sinonasal sarcomas are rare and heterogeneous in nature. Continuously collecting data influencing the prognosis is fundamental for optimizing therapeutic assessment of this highly destructive neoplasm.