Observation of the change of the dental implant stability and bone density evaluation methods

Abstract

Purpose: The aim of this study was to examine the correlation of the subjective and the objective evaluation of edentulous ridge bone quality, and to evaluate the change of the dental implant stability in each bone density group for early healing period after implant installation. Methods: Sixty-seven implants(Osstem implant ® , Seoul, Korea) were included in this study. We evaluated the bone density by 2 methods. The one was the subjective method which was determined by practitioner's tactile sense, the other was the objective bone type was based on Hounsfield units. The implant stability in each bone type group was assessed by resonance frequency analyzer(Osstell mentor ® ). Data were analyzed for the change of the implant stability, and they were compared to verify the difference of groups at the time of installation, 2, 6, 10, 14 weeks postoperatively. Spearman's correlation was used to demonstrate the correlation between the subjective and the objective evaluation of the bone density, and analysis of variance(ANOVA) was used to analyze the differences of implant stability at each time point. Results: There was no close relation between the subjective and the objective evaluation of the bone density(r= 0.57). In the subjective groups, there was statistically significant difference between the type 1 and 3 at 10 weeks and between the type 2 and 3 at 14 weeks. In the objective groups, there was no statistically significant difference between the D 1, 2, 3, 4, and 5 group with regard to RFA from baseline to 14 weeks(P>0.1). Conclusions: The implant stability increased over time during the study, and it was improved with bone density proportionally after 2weeks postoperatively. It is recommended that the decision of bone density is base on Hounsfield unit for implant loading time. (J Korean Acad Periodontol 2009;39:185-192)

Accuracy of different electronic torque drivers: A comparative evaluation

“…Biomechanical analysis with hard tissue interface is mainly conducted through physical means. Percussion reaction testing16 is a simple method that involves hitting the top of an implant with a metal object and listening to vibration sound; the results cannot be quantified and it is difficult to detect decrement of sound quality or amplified resonant frequency. Tooth mobility measurement [Periotest (Siemens AG, Benssheim, Germany)] and Dental Fine Tester17 use an exclusive handpiece; the reliability of the measured value decreases according to the positions of the abutment and handpiece.…”

“…Tooth mobility measurement [Periotest (Siemens AG, Benssheim, Germany)] and Dental Fine Tester17 use an exclusive handpiece; the reliability of the measured value decreases according to the positions of the abutment and handpiece. The reverse torque test161819 detects abnormalities by applying counterclockwise torque at 20 Ncm to the implant. This is effective for detecting implant osseointegration failure but causes irreversible deformation in juveniles.…”

“…This is effective for detecting implant osseointegration failure but causes irreversible deformation in juveniles. Measurements of cutting force, insertion torque, and cutting resistance on insertion16 do not harm the area of implant placement but assessing bony tissues only on insertion has the disadvantage of being difficult to reproduce. Resonance frequency analysis202122 is nondestructive testing of the relationship between the implant and the surrounding bone using electrical vibration.…”

“…Histological and histomorphometric analyses are quantitative methods for testing the bones and implants, allowing simultaneous observation of the implant and the surrounding soft and hard tissues; however, as destructive tests, they have limited clinical utility. The pull-out and push-out test162526 has been used for measuring the shear bond strength of the cylinder-type implant, and the degree of micro-level implant osseointegration can be quantified as biomechanical bond strength.…”