Detectability of biomechanical risk factors in patients with fixed dentures on dental implants

BACKGROUND: Long-term results of orthopedic rehabilitation of patients with partial and total tooth loss using implants revealed a considerable number of failures and complications. Periodontopathogenic microfloral activity resulting from poor oral hygiene is the most studied cause of implant removals and development of periimplant chronic inflammation. To a much lesser extent, biomechanical risk factors influence the effectiveness of prosthetics on implants. In particular, information on adverse biomechanical factors in individuals with dental implants is insufficient.

AIM: To analyze the frequency of detection of unfavorable biomechanical conditions for the functioning of prostheses on implants.

MATERIALS AND METHODS: Based on the results of clinical and X-ray examination of 417 patients with 1,222 intraosseous implants, who have completed fixed prosthetics for partial absence of teeth 10 years ago, the biomechanical conditions for the functioning of implants were evaluated. The density and volume of the bone tissue, previous bone grafting, cortical bone thickness, implant length and diameter, characteristics of the junction with the abutment, position of the implant relative to the alveolar ridge, ratio of the implants and prosthetic units in fixed prostheses, presence of occlusive supracontacts on implants, degree of replacement of dentition defects, presence of approximal contacts, association with teeth, and load type were collected.

RESULTS: A thin cortical bone, as an inadequate biomechanical condition, was found in 65.7% of the implants, low bone density in 32.3%, and insufficient and uncompensated bone volume in 15.5%. Implant overload caused by the absence of approximal contacts with adjacent teeth or prostheses was detected in 60.3% of implants, occlusive supracontacts in 58.4%, installation of narrow and short implants 29.1% and 15.5%, respectively, and installation of implants with a slope in 33.1%. Incomplete replacement of the dentition defect and consequently increased functional load were found in 57.3% and 28.1% of implants, respectively, and an insufficient number of support implants were found in 21.5%. The combination of implants with teeth with bridge prosthesis was typical for 19.2%.

CONCLUSION: In modern implantology, inadequate biomechanical conditions influence the qualification of doctors, motivation of patients to the ideal volume of prosthetics on implants, andfunctioning of fixed prostheses on intraosseous implants.