ABSTRACT

Aim: This within-subject study report to investigate masticatory efficiency and maximum bite force of Locator and telescopic crown attachments used to retain maxillary implant overdentures.

Materials and methods: Six edentulous patients (3 males and 3 females) received 4 implants in the anterior maxillary region between the maxillary sinuses using a standardized 2 stage surgical approach. Six months after osseointegration, the implants were loaded either by Locator or telescopic maxillary overdentures in a cross-over study design. Masticatory efficiency was performed using the 2-colored gum mixing ability test. The gum was chewed for 5, 10, 20, 30, and 50 cycles, and the images of the chewed gum were analyzed using a Photoshop program to calculate the unmixed fraction (UF). Also, maximum bite force was evaluated using a bite-force transducer. Chewing efficiency and maximum bite forces were evaluated 3 months after wearing each overdenture.

Results: The success rate was 100% in both groups. There was a trend for a decrease in UF (ie improved masticatory efficiency) with the increase in the number of masticatory cycles. Telescopic maxillary overdentures showed significantly lower UF (ie higher masticatory efficiency) and higher maximum bite force than Locator maxillary overdentures

Conclusion: Telescopic attachments are recommended for maxillary implant overdentures as it had improved masticatory efficiency and maximum bite force than Locator attachments

Purpose: This study aimed to investigate the effect of attachment type, maximum occlusal force, denture deformation, and other confounding factors on marginal bone loss of two-implant overdentures after 1 year.

Materials and Methods: Ninety edentulous patients received two implants in canine areas of the mandible using the computer-guided flapless surgical technique. Three months later, overdentures were connected to the implants with bar, resilient telescopic, and resilient stud attachments. Marginal bone loss was evaluated using standardized digitized periapical radiographs. Maximum occlusal forces were evaluated using a digital bite-force meter. Denture base deformation (denture strains, μm) was evaluated using strain gauges bonded to the polished surface of the denture at the level of the attachments. Regression analysis was adopted to find the relation between marginal bone loss and the following confounders (age, sex, mandibular bone height, period of edentulism, number of previous dentures, attachment type, maximum occlusal force, and denture strains).

Results and Conclusion: Telescopic overdentures showed the highest marginal bone loss and maximum occlusal force, followed by bar overdentures, and stud overdentures demonstrated the lowest values. The highest denture strains were noted with bar overdentures, followed by telescopic overdentures, and stud overdentures showed the lowest strains. Age (P = .022), mandibular bone height (P = .023), number of previous dentures (P = .004), maximum occlusal force (P ≤ .001), and denture strains (P = .048) were significantly correlated with marginal bone loss. For every 1-year increase in age, there was a decrease in bone loss by 0.3%. For every 1-mm increase in bone height, there was an increase in bone loss by 1%. For every one increase in the number of worn dentures, there was a decrease in bone loss by 4.2%. For every 10-N increase in maximum occlusal force, there was an increase in bone loss by 6.4%. For every 10-μm increase in denture strains, there was an increase in bone loss by 0.21%. Sex, time of edentulism, and attachment type did not demonstrate a significant correlation with marginal bone loss. Int J Oral Maxillofac Implants 2022;37:391–399. doi: 10.11607/jomi.8982