Peri-implant bone length changes and survival rates of implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height

PURPOSE: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. METHODS: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The peri-implant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. RESULTS: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. CONCLUSIONS: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.

The effect of palatal height on the Korean vowels / 대한치과보철학회지

PURPOSE: The purpose of this study was to analyze the influence of palatal height on Korean vowels and speech intelligibility in Korean adults and to produce baseline data for future prosthodontic treatment. MATERIAL AND METHODS: Forty one healthy Korean men and women who had no problem in pronunciation, hearing, and communication and had no history of airway disease participated in this study. Subjects were classified into H, M, and L groups after clinical determination of palatal height with study casts. Seven Korean vowels were used as sample vowels and subjects' clear speech sounds were recorded using Multispeech software program on computer. The F1 and the F2 of 3 groupswere produced and they were compared. In addition, the vowel working spaces of 3 groups by /a/, /i/, and /u/ corner vowels were obtained and their areas were compared. Kruskal-Wallis test and Mann-Whiteny U test were used as statistical methods and P < .05 was considered statistically significant. RESULTS: There were no significant differences in formant frequencies among 3 groups except for the F2 formant frequency between H and L group (P = .003). In the analysis of vowel working space areas of 3 groups, the vowel working spaces of 3 groups were similar in shape and no significant differences of their areas were found. CONCLUSION: The palatal height did not affect vowel frequencies in most of the vowels and speech intelligibility. The dynamics of tongue activity seems to compensate the morphological difference.