Abstract
Purpose: Clasp-penetrating oral injury caused by removable partial dentures is basically a minor injury but can also cause complications such as continuous bleeding. No systematic investigations of clasp injury have been undertaken. The aims of this study were to reveal the characteristics of clasp injury and estimate variables associated with clasp injury of the oral mucosa. Methods: This retrospective study used clasp injury as the outcome variable, with primary predictor variables of demographic characteristics, medical history, local characteristics, and denture design, including the site of the affected clasp. Denture type was examined according to the classification of Kennedy. Collected data were statistically analyzed using the χ(2) test or Fisher's exact test and the level of significance adopted was 5%. Results: This report consists of 73 cases (36 men and 37 women), of which 31 cases had precise denture information. Among them, clasp injuries were more common with Class I (51.6%) and Class II (32.3%) dentures (p < .001). Premolar (64.5%) and canine clasps (32.3%) were significantly more frequently involved (p < .001). Conclusion: Clasp injury of the oral mucosa was significantly more common on the tongue, and mandibular free-end saddle dentures with premolar or canine clasps were the most notable risk factor for clasp-penetrating injury of the oral mucosa.