Enhancement of a Caries-resistant Oral Environment on Treatment Using Prosthesis

Patients: A 55-year-old woman with complaints of esthetic disturbance and masticatory dysfunction visited Osaka Dental University Hospital. The remaining upper teeth showed severe degradation of the coronal dentine because of caries. Additionally, the vertical stop in the molar region was lost. In the initial treatment, an overdenture was placed for urgent improvement of the chief complaint. We diagnosed the patient as having esthetic disturbance and masticatory dysfunction due to many decayed and missing teeth. Subsequently, we performed oral surgical, endodontic, and periodontal treatments of the remaining teeth based on the diagnosis. According to the patient’s request, fixed prostheses, i.e., crowns and fixed partial dentures, were selected as the final prostheses. On the other hand, since caries progression is possible during a long-lasting treatment, the patient’s oral environment has been monitored using a saliva test to estimate caries activity. We selected the following 4 factors as the oral environmental factors: the stimulated salivary flow rate, buffering capacity, and salivary microbial counts of mutans streptococci and lactobacilli. The first examination revealed a high-risk oral environment. However, lactobacilli counts decreased immediately after the cementing of fixed prostheses and were low-risk at recall. Other factors remained at low-risk-levels throughout the treatment period.Discussion: To improve esthetic disturbance and masticatory dysfunction, prosthetic treatment was performed, and the progressive degradation of tooth structures due to caries was prevented. The oral environment was examined by the saliva test during therapy. After the treatment, the lactobacilli counts decreased. This is thought to be the result of removing caries and poorly fitting restorations.Conclusion: By means of the saliva test, we confirmed the improvement in the oral environment following proper prosthetic treatment.