ABSTRACT
Long-term dental implant success is dependent on biocompatibility and osseointegration between the bone and the implant. Surface modifications such as laser-induced microgrooving which increase contact area can enhance osseointegration by establishing and directing a stable attachment between the implant surface and peri-implant bone. The objective of this study was to evaluate pre-osteoblast proliferation, morphology, and differentiation on titanium alloy (Ti64) surfaces-Laser-Lok© (LL), resorbable blast textured (RBT), and machined (M)-compared to tissue culture plastic (TCP) control. We hypothesized the LL surfaces would facilitate increased cellular alignment compared to all other groups, and LL and RBT surfaces would demonstrate enhanced proliferation and differentiation compared to M and TCP surfaces. Surface roughness was quantified using a surface profilometer, and water contact angle was measured to evaluate the hydrophilicity of the surfaces. Cellular function was assessed using quantitative viability and differentiation assays and image analyses, along with qualitative fluorescent (viability and cytoskeletal) imaging and scanning electron microscopy. No differences in surface roughness were observed between groups. Water contact angle indicated LL was the least hydrophilic surface, with RBT and M surfaces exhibiting greater hydrophilicity. Cell proliferation on day 2 was enhanced on both LL and RBT surfaces compared to M, and all three groups had higher cell numbers on day 2 compared to day 1. Cell orientation was driven by the geometry of the surface modification, as cells were more highly aligned on LL surfaces compared to TCP (on day 2) and RBT (on day 3). At day 21, cell proliferation was greater on LL, RBT, and TCP surfaces compared to M, though no differences in osteogenic differentiation were observed. Collectively, our results highlight the efficacy of laser microgrooved and resorbable blast textured surface modifications of Ti64 for enhancing cellular functions, which may facilitate improved osseointegration of dental implants.
ABSTRACT
OBJECTIVE: To examine whether self-reported hearing difficulty is an accurate measure of hearing loss compared with standard hearing screening with pure tone audiometry in rural and urban communities. DESIGN: Convenience sampling. SETTING: Urban and rural areas of Western Australia. PARTICIPANTS: A total of 2090 participants (923 men; 1165 women; 2 unknown) aged 20-100 years presenting for community-based hearing screening in urban (982) and rural (1090) areas. INTERVENTIONS: Self-reported hearing difficulty assessed with the Hearing Handicap Inventory for the Elderly - Screening questionnaire. Hearing loss defined as average hearing thresholds >25 dB in the better ear using screening audiometry conducted at 500, 1000, 2000 and 4000 Hz. MAIN OUTCOME MEASURES: Nil. RESULTS: The Hearing Handicap Inventory for the Elderly - Screening was sensitive (≥60 years = 76.69%; <60 years = 71.67%) but not specific (≥60 years = 45.15%; <60 years = 49.63%) for identifying hearing loss. The <60 age group had a hearing loss prevalence of 25.6%, and a false-positive rate of 67.12% compared with a prevalence of 69.12% and false-positive rate of 29.77% for the ≥60 age group. For all ages, rural participants were more likely to have a disabling hearing loss (odds ratio 2.04 (95% confidence interval, 1.55-2.67); χ(2)(1) = 27.28; P < 0.001), but there were no significant differences in hearing aid uptake. CONCLUSIONS: Patients in rural areas presenting for hearing screenings are more likely to suffer hearing loss than adults in urban areas. We suggest rural health practitioners incorporate a self-reported hearing loss questionnaire into health check-ups for adults, particularly patients aged ≥60 years due to the high prevalence of hearing loss in this group.
