In Vivo Evaluation of the Early Implant Screw Loosening as Affected by Different Types of Angulated Abutments and altered Loadings: An Original Research Study

Abstract

Aim: This study aims to evaluate the early implant screw loosening as affected by different types of angulated abutments and altered loading.

Materials and Methods: A total of 50 patients sought replacement for a missing mandibular right first molar, with 36 choosing dental implants. Eligibility included voluntary consent, good health, and sufficient alveolar ridge condition, while immunocompromised individuals, smokers, and those with mental health or substance abuse issues were excluded. A Cone Beam Computed Tomography (CBCT) evaluation was performed before surgery, and participants used chlorhexidine mouthwash. Under local anaesthesia, a mucoperiosteal flap was reflected for implant placement. Two months later, a healing abutment was added, and by three months, the implant-supported prosthesis was fitted. The 36 patients were divided into two groups: Group 1 received angulated abutments (15°, 25°, 35°), while Group 2 had straight abutments. Implant mobility was assessed at three- and six-month post-placement, with nine patients receiving immediate loading.

Statistical Analysis and Results: This study involved 36 patients, consisting of 21 males and 15 females from diverse backgrounds. Patients were divided into two groups for comparison. Group 1 included 18 patients fitted with implant-supported prostheses featuring angulated abutments at 15°, 25°, and 35°. Their stability was evaluated using advanced radiofrequency analysis. Group 2 also had 18 patients but received traditional straight abutments. After three months, Group 1 showed an average Implant Stability Quotient (ISQ) of 45.1 ± 5 Ncm at 35°, which improved to 50.1 ± 4 Ncm after six months. In Group 2, ISQ values were recorded as 55.5 ± 4 Ncm for immediate loading and 65.4 ± 5 Ncm for delayed loading after three months, rising further to 69.4 ± 4 Ncm and 72.4 ± 5 Ncm, respectively, after six months. The data underwent one-way ANOVA analysis also.

Conclusion: This study concluded that as the angle exceeds upto 35 degrees, the risk of loosening increases at both three- and six-month post-implant placement. Immediate loading creates greater stress on the implant-abutment connection, leading to higher mobility and a greater chance of loosening due to compromised screw tightness. The authors anticipate for further research to better understand these mechanisms and improve clinical practices.