Clinical evaluation of retention and biting force in complete mandibular overdentures retained by two implants using a solitary ball and socket versus solitary bar and clip attachments: A crossover study

Objectives: a clinical evaluation of retention and biting force in complete mandibular overdentures retained by two implants using a solitary ball and socket versus solitary bar and clip attachments. Materials and methods: Fourteen completely edentulous male patients aged 49 to 65 were selected and received a maxillary complete denture and two mandibular complete dentures. Each patient received bilateral dental implants placed in the canine areas using a stereolithographic guide. They were grouped according to the period of wearing the prosthesis into: the conventional complete denture group (CD Group), using two duplicated mandibular dentures over three months; ball and socket attachment group (Ball Group), retaining the mandibular overdenture with ball and socket attachments for 3 months; and solitary bar and clip group (Bar Group), using custom bar and clip attachments for 3 months. Retention and maximum biting force were evaluated immediately (T0), one (T1), two (T2), and three months (T3) after denture insertion, and each attachment installation. Results: Results showed significant differences in retention force among groups, with the highest retention in the bar overdenture, followed by the ball overdenture, and the lowest in the complete denture. Maximum bite force also varied significantly, with the bar overdenture having the highest force, the ball overdenture next, and the complete denture the lowest. Conclusions: Custom-made solitary bar and clip attachments offer improved retention and biting force for mandibular overdentures compared to ball attachments. Additionally, they are customized to any implant system available on the market.