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ePaper created 2017-01-25, 09:48:20 | version 1.38.0
1_2017 22 gingiva; 1 = mild inflammation, slight change in color, slight edema, and no bleeding on probing; 2 = moderate inflammation, redness, edema, glazing, and bleeding on probing; and 3 = se- vere inflammation, marked redness and edema, ulceration and tendency to spontaneous bleed- ing. Implant and prosthetic survival and success rates were evaluated by an independent dentist (EP). Complications were assessed and treat- ed by a non-blinded treating clinician (GP). The marginal bone remodeling was evaluated by an independent radiologist. An independent blind- ed dental hygienist who was not involved in the study performed all of the periodontal measure- ments. _Statistical analysis Statistical analysis was performed using SPSS for Windows (Version 18.0; SPSS, Chica- go, Ill., U.S.). Descriptive analysis was performed using mean, standard deviation and frequency distribution. A life table analysis of implant cu- mulative survival rates (CSRs) was calculated. Kaplan–Meier survival analysis was performed to allow estimation of survival over time, even when patients dropped out or were followed for different lengths of time. The Wilcoxon signed- rank test for paired data was utilized to compare overall bone levels between baseline (implant placement) and follow-ups in both healed and post-extraction sites, and to compare bone re- modeling between post-extraction and healed sites at the last follow-up examination. The im- plant was used as the statistical unit of the anal- ysis. All statistical comparisons were conducted at the 0.05 level of significance. _Results All 27 selected and analyzed patients met the inclusion criteria. Patients received a total of 160 NobelActive implants (22 narrow diameter, 106 regular diameter and 32 wide diameter) with a moderately rough surface (highly crystalline and phosphate-enriched titanium oxide). One hun- dred and five implants were placed into healed sites and 55 into post-extraction sockets. Each patient received at least one post-extraction implant. Patients were clinically followed for up to five years. At the last follow-up, no patients had dropped out and no deviation from the orig- inal protocol had occurred. All of the collected data were included in the statistical analysis. Only one post-extraction implant failed in one patient, who showed poor oral hygiene, during the second year, and showed clinical signs of mobility and infection, resulting in an overall implant CSR of 99.4%. The life table analysis is summarized in Table 1. All prostheses were in situ at the last follow-up, accounting for a cu- mulative prosthetic survival rate of 100% up to five years after insertion. Two implants (1.25%) showed marginal bone remodeling of greater than 3 mm at the last follow-up. However, none of the implants presented with an exposed im- plant neck, and no surgical intervention was performed. All of the affected patients under- went nonsurgical therapy consisting of manual debridement using titanium curettes and a gly- cine-based air–powder abrasive device, and local application of antimicrobial agents (minocycline HCl 1 mg, Arestin, Ora- Pharma, Horsham, Pa., U.S.), followed by oral hygiene instructions and motivation, together with a strict follow-up pro- tocol. At the subsequent follow-ups, the bone recession had stopped and the soft tissue re- mained stable. No other biological or mechanical complications occurred during the entire fol- low-up period, resulting in a cumulative implant and prosthetic success rate of 97.9%. At the last follow-up (mean of 29 months), the marginal bone remodeling was -0.58 ± 0.98 mm. Implants placed into post-extraction sockets (0.42 ± 0.99 mm) showed statistically lower marginal bone remodeling compared with implants placed into healed sites (-0.67 ± 0.97 mm; P = 0.026). At the last follow-up session, bleeding after care- ful insertion of a periodontal probe 1 mm into the mucosal sulcus parallel to the abutment sur- face was detected around three implants (1.6%). Twelve patients with 68 implants showed a slight amount of plaque around the implant–abutment interface; thus, the overall plaque score was 36.0% and 44.4% at implant and patient level, respectively. The gingival index was reported as 90.5% normal gingiva, 7.9% with mild inflam- mation and 1.6% with moderate inflammation. _Discussion This study retrospectively evaluated the suc- cess and survival rates of variable-thread ta- pered-body implants placed into post-extraction or healed sites in the maxilla using computer-as- sisted template- guided surgery in combination with a specially designed two-piece radiographic stent.21 The main limitations of this study are its retrospective nature, which may have limited the data collection, and the analysis of possible vari- ables (soft-tissue thickness, time of placement or loading) that may have influenced the bone re- sorption. Another limitation is the limited num- ber of participants. However, this investigation may be considered as a pilot study for future expert article _ chirurgia guidata