Influence of RPD Placement on Mobility of Periodontally Weakened Teeth

Objectives: Mobile teeth weakened by periodontitis has been reported to be at higher risk of loss, even when supportive periodontal therapy (SPT) is applied. Prosthodontists sometimes attempt to protect weakened mobile teeth by splinting them against one another using prostheses. However, the splinting effect of prostheses remains to be clinically clarified. The purpose of this prospective clinical trial was to investigate the effect of removable partial dentures (RPDs) designed to splint remaining teeth on the tooth mobility of PRD abutments using a Periotest®.
Methods: One hundred twenty-six RPD abutments (n=126: 59 with direct retainers and 67 without direct retainers) in 25 partially edentulous patients under the SPT phase (21 female, 4 male; mean age: 68.2±8.90) who were diagnosed with periodontitis at first visit were evaluated. RPDs designed to splint remaining teeth were delivered to the subjects. Clinical periodontal records including tooth mobility were measured on the day of denture placement (baseline) and at 1 week, 1 month, and 3 months after the placement. Tooth mobility was examined using the Periotest®. At baseline, abutment teeth were divided into two groups based on Periotest value (PTV) without RPD placement: <10 and ≥10 for normal teeth group (NG: PTV=4.31±2.25) and mobile teeth group (MG: PTV=20.6±10.4), respectively.
Results: No significant difference was found between a follow-up period and the baseline in each group, except for PTV of abutment teeth with direct retainers at 1 month after RPD placement, which was significantly higher than the baseline (p=0.016). However, PTVs at 3 months after RPD placement were higher than the baseline in each group, even if there was no significant difference.
Conclusions: It suggested that unfavorable adverse risk of RPD placement on periodontally weakened teeth was equal to or lower than that on normal teeth from the viewpoint of tooth mobility.