Is Dry Mouth a Risk Factor for Peri-implantitis?

Objectives: The effect of dry mouth on dental implants is unclear. We investigated the effect of dry mouth on the hard and soft tissue around dental implants using an animal model.
Methods: We extracted the bilateral maxillary first molars from 5-week-old male Wistar rats. We placed titanium implants 3 weeks after the extraction, followed by healing abutments after a further 3 weeks. After osseointegration, the rats were divided into control and dry-mouth groups. The bilateral submandibular and sublingual glands were removed from the rats in the dry-mouth group and those in the control group underwent a sham operation. Silk ligatures were placed on one side of the abutment in each rat. Secretion of saliva was induced by intraperitoneal administration of pilocarpine and the volume of secreted saliva was measured. Peri-implant tissues extracted at 4 weeks post-ligation were analyzed by micro-computed tomography and hematoxylin-and-eosin staining. Statistical evaluation was performed by Student’s t-test and one-way analysis of variance. The protocol was approved by the Animal Committee of Kyushu Dental University (no. 18-012).
Results: Pilocarpine-induced secretion of saliva was significantly lower in the dry-mouth group than the control group (p < 0.01). No implant failure occurred in either group. Micro-computed tomography revealed that the degree of marginal bone loss around dental implants was comparable in the control and dry-mouth groups on the non-ligated side but was significantly increased in the dry-mouth group compared to the control group on the ligated side (p < 0.05). There was no difference in the histology of peri-implant soft tissue between the control and dry-mouth groups.
Conclusions: The results suggest that dry mouth with poor plaque control induces marginal bone loss around dental implants.