Impact of xerostomia on dental treatment outcomes: a systematic review

Background Xerostomia, commonly caused by medications, radiotherapy, or Sjögren’s syndrome, impairs saliva’s protective functions and increases risk of caries, restoration failure, prosthesis complications, and peri-implant bone loss. However, its overall impact on dental treatment outcomes has not been systematically reviewed. Methods A systematic review was conducted following PRISMA guidelines. Electronic databases were searched, and studies evaluating the impact of xerostomia on dental treatment outcomes, including restorations, implants, prostheses, and periodontal therapy, were included. Data extraction was performed in duplicate, and risk of bias was assessed using RoB 2.0 for randomized trials and ROBINS-I for non-randomized studies. Certainty of evidence was graded using the GRADE approach. Results Sixteen studies were included in the review. Implant survival in xerostomic patients was generally high (> 90%) but slightly lower in those with radiation-induced xerostomia. Restoration longevity was consistently reduced, with higher failure and recurrent caries rates in Sjögren’s syndrome and post-radiotherapy patients. Limited evidence suggested no major differences in periodontal treatment response, while no eligible studies directly assessed denture retention. Overall, most studies were small, heterogeneous, and at moderate to serious risk of bias. Conclusions Xerostomia reduces restoration longevity and may affect periodontal therapy, while implants generally show good survival. Evidence is limited and biased, highlighting the need for preventive care and stronger clinical studies.