In this retrospective study, we identified risk factors for tooth loss in patients undergoing mid–long-term maintenance therapy. We surveyed 674 maintenance patients for ≥5 years after active treatment who visited a dental clinic between January 2015 and December 2016. Of these, 265 were men (mean age 54.6 ± 8.0 years old) and 409 were women (mean age 54.0 ± 7.9 years old). Study variables included patient compliance, sex, number of teeth lost, cause of tooth loss (dental caries, periodontal disease, root fracture, others, vital or non-vital teeth), age at start of maintenance, number of remaining teeth at start of maintenance, smoking, use of salivary secretion inhibitors, presence of diabetes mellitus, condition of periodontal bone loss, and use of a removable denture. Most lost teeth were non-vital teeth (91.7% of all cases) and the most common cause of tooth loss was tooth fracture (62.1% of all cases). A statistically significant risk factors for tooth loss was number of remaining teeth at the start of maintenance (p = 0.003).

Tooth loss represents a diffused pathologic condition affecting the worldwide population. Risk factors have been identified in both general features (smoking, diabetes, economic status) and local tooth-related factors (caries, periodontitis). In this retrospective study, we examined the data of 366 patients with a large number of remaining teeth (≥25) undergoing maintenance therapy in order to identify specific risk factors for tooth loss. The number of remaining teeth, number of non-vital teeth, and number of occlusal units were investigated for their correlation with tooth loss. The mean follow-up of patients was 9.2 years (range 5 to 14). Statistically significant risk factors for tooth loss were identified as number of remaining teeth at baseline (p = 0.05), number of occlusal units (p = 0.03), and number of non-vital teeth in posterior regions (p < 0.001). Multiple logistic regression showed that the number of occlusal units and number of non-vital teeth in the posterior regions were significantly associated with a greater risk of tooth loss (odds ratio 1.88 and 3.17, respectively). These results confirm that not only the number of remaining teeth, but also their vital or non-vital status and the distribution between the anterior and posterior regions influence the long-term survival.

Background: Tooth loss is generally considered the final outcome of oral disease. This retrospective study was performed to identify risk factors for tooth loss in patients undergoing long-term maintenance therapy. Methods: We surveyed 1145 adult patients who underwent maintenance therapy for ≥5 years after they had undergone active treatment from January 2015 to December 2016 and established a baseline status. The study variables were patient compliance, sex, number of teeth lost, cause of tooth loss, age at start of maintenance, number of remaining teeth at start of maintenance, duration of maintenance, smoking status, use of salivary secretion inhibitors, and diabetes mellitus. Additionally, 57 patients who did not undergo maintenance therapy were surveyed to examine and compare the effects of maintenance therapy. Statistical analyses were performed to assess the correlation of each variable with tooth loss. Results: The average number of teeth lost under maintenance therapy was 0.07/year. Significantly fewer teeth were lost in the maintenance than non-maintenance group. Most of the teeth lost were non-vital teeth, and the most common cause of tooth loss was tooth fracture. Patient age, number of remaining teeth at start of maintenance, use of salivary secretion inhibitors, and diabetes mellitus were related to tooth loss. Conclusions: To the best of our knowledge, this is first large-scale study of tooth loss in patients undergoing long-term maintenance therapy within a general dental clinic. Our findings demonstrate that starting maintenance therapy when patients are younger and possess more teeth may prevent future tooth loss.