The purpose of this study was to determine if intraoral scanners (IOS) are useful for dental hygiene instruction. The dental plaque of eight volunteers with healthy dentition was stained with a plaque-disclosing solution, and the O'Leary Plaque Control Record (PCR) was measured by direct observation and by evaluating IOS images. PCR values were higher for IOS images than for direct observation. The difference was greatest for the lingual surface of mandibular anterior teeth. Use of IOS for dental plaque examination might be useful as a novel method for dental hygiene instruction.

Objectives:The purpose of this experimental study was to investigate the correlation between the frictional resistance torque of tap drilling prior to implant placement and the primary stability after implant placement. Material and Methods: Solid rigid polyurethane bone blocks of four different densities were used in this study. A computerized surgical implant motor device was utilized to measure the frictional resistance torque of tap drilling. After the tap torque was measured, the dental implants were inserted at the prepared sites. During the implantation, the insertion torque was recorded, and resonance frequency analysis was performed, the value of which was calculated as the implant stability quotient. Thereafter, the correlation between the tap torque and the primary stability of the implant was evaluated and compared with the standard drilling protocol. Results: A significant positive correlation was found between the tap torque and insertion torque (Pearson's r = 0.88, P < 0.0001). Similarly, there was a positive correlation between the tap torque and implant stability quotient (Pearson's r = 0.69, P < 0.0001). Conclusions: These results suggest that measurement of the frictional resistance torque of tap drilling prior to implant placement could provide helpful information for implant primary stability.

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This study aimed to compare the implant stability of an implant-porous titanium complex with that of an implantporous hydroxyapatite complex. Implant-porous titanium and implant-porous hydroxyapatite complexes were placed in the tibia of four New Zealand white rabbits. After 4 weeks, the implant stability quotients (ISQs) were measured. Histological observations and histomorphometric measurements were performed. There was no significant difference in the ISQ values and bone implant contact ratios between both groups. In contrast, the newly formed bone area ratios were significantly lower in the implant-porous titanium than in the implant-porous hydroxyapatite. Histologically, osteoconduction was observed in both groups in the upper cortical bone region; however, lesser new bone was formed in the lower bone marrow region in the implant-porous titanium than in the implant-porous hydroxyapatite. In conclusion, implant-porous titanium and implant-porous hydroxyapatite complexes have favourable implant stability. However, osteoconduction was insufficient with the implant-porous titanium complex compared with the implant-porous hydroxyapatite complex. This may be improved by making titanium bioactive through surface treatment or other means.