# Risk Factors Associated with Cusp Fractures in Posterior Permanent Tenth--A Cross-Sectional Study
## 4 Discussion
(2004) [13] observed two risk indicators for dental fractures: presence of fracture lines and the crown volume of a tooth filled by a restoration. However, a critical analysis [20] questions these indicators since the fracture lines could be interpreted as the beginning of the fracture per se, especially regarding the accuracy of the restoration volume calculation in cases where the restoration had been lost. To date, no study has been able to quantify such risk and dissociate the main factors associated with variables in the binomial cavity preparation/restorative material. What is the number of faces involved? What is the cavity width? Or, perhaps, what is the restorative material? Questions raised given the change in the dentistry scene, and the use of adhesive systems in posterior teeth, have reached considerable proportions in the last decades [19; 28; 29]. Regarding restorative materials, teeth restored with resin or amalgam fractured equally. It is normally believed that teeth with amalgam restorations are more associated with fractures than those restored with composites. However, given the increased indication of composites restorations in posterior teeth associated with etching and the use of last generation adhesives, the assessing of these premises was important for this study [1; 12; 15; 20; 28; 29]. Nevertheless, the results pointed out the restorative material did not influence the fractures' development, reinforcing, once again, that cavity preparation is a more important factor than restoration material. Consequently, no restorative material would restore cusp stiffness and cusp deflection would increase at the expense of cavity extension, allowing failure, microleakage at the restorative interface, and tooth fatigue over time [17]. One previous study evaluated 10.082 teeth restored with amalgam and 787 with composite. Authors observed that the frequency of fractured cusps in each group was not considered statistically different, both of which were considered acceptable from the point of view of restoration and tooth durability [12]. Based on the analyses here performed, sex, age, arch, restorative material (amalgam or resin), endodontic treatment, or type of food were not factors that were directly associated with dental fractures, although they have been considered previously [1; 2; 5; 7; 9; 11; 13; 15]. On the other hand, fractures were more common in teeth where the restoration was 1/3 wider than their distance and/or involved more than three restored surfaces. Among patients with fractured teeth, only 20% reported bruxism/clench. The idea of covering functional cusps or even all cusps was left opened for discussion: how can we be protecting the cusps by wearing them? To preemptively cover the cusps would today be an analogy for the \"Extension for Prevention\" by [PERSON] (1910) [30], which established the philosophy of \"wearing to prevent\"? Moreover, even if the dentist chooses to cover them, he/she should know the lingual cusps are most prone to fractures, not necessarily the LUBL. In this way, the null hypothesis in this project was rejected since even non-functional cusps fractured more than the functional cusps. Data from this study strongly encourage earlier and minimally invasive preventive approaches preserving unsupported enamel and restricted to selective caries removal, with special attention to marginal ridge preservation since they are joists joining the buccal and lingual cusps. For those compromised teeth, with the classic indication of cusp coverage, randomized studies based on adhesive procedures and ceramic and resin restorations should be established, restoring only the missing parts since many principles were established based on cast restorations. This study, following a cross-sectional design, required a rigorous data collection and compilation, including clinical observations, examiner training and calibration, and establishment of inclusion and exclusion criteria, among other methodological characteristics, ensuring data reliability.