## 4 Discussion
Therefore, reduced periodontal support (tooth loss and implants-less PDL) may decrease the threshold level of the mechanoreceptors function. On the other hand, remote mechanoreceptors can be responsible for the supra-threshold touch sensitivities of both teeth and implants [9]. These results are in agreement with those of [PERSON] et al. [43], who reported that the maximal occlusal force was significantly higher in subjects with natural dentition (control group) than in patients with fixed prostheses and implants (test group). Similarly, [PERSON] et al. [44] found the highest bite forces in subjects with full natural dentition, while groups of individuals with fixed partial dentures, removable partial denture, and complete dentures exhibited biting forces of 80%, 35%, and 11%, respectively, when expressed as a percentage of the values in the natural dentition group. In contrast, [PERSON] et al. [12] reported that patients with implant-supported bridges had an equal masticatory muscle function as control patients with natural teeth or with tooth-supported bridges. In view of the studies that demonstrated higher occluding forces on teeth adjacent to dental implants [23] and a higher incidence of VRFs in endodontically treated teeth adjacent to implants [24], our findings could be interpreted as a psychophysical fear of damaging abutment teeth, implants, or prostheses. This concern about causing damage or generating pain and tenderness in the teeth, supportive structures, temporomandibular joint, or masticatory muscles during the measurements might have a negative influence on bite force measurements [1]. There are other possible reasons that can generate discomfort biting on a successful dental implant. In the edentulous jaw or with implants, the activity of masticatory muscles and thus the bite force is monitored by mucosal and periosteal mechanoreceptors not by receptors in the periodontal ligament [19]. Another reason can be the modified occlusion applied to implants in order to reduce the occlusal force during loading conditions, as well as the stress in the peri-implant surroundings [18]. Except for bite force measurements, there are other methods to evaluate quantitatively biomaterial biodegradation and bone formation around implants such as histomorphometry, microCT, microMRI, or the combination of them [45]. Our results demonstrated that sex has a significant influence on the maximal bite force, with higher values for men, regardless of the experimental group. This finding is in agreement with previous studies, which also have reported that the mean maximal bite force exerted by men is greater than that exerted by women [20,46,47]. This can be explained by the fact that females have smaller teeth, which corresponds to a smaller periodontal ligament area and consequently might deliver a lower bite force than seen in men. Another possible explanation could be the greater muscular potential of males, which may be attributed to the anatomic differences between different sexes [48]. In this context,the masseter muscles of males have muscle fibers with a larger diameter and a greater sectional area than those of females [49]. This result is of clinical relevance, because if so we might plan our treatment plan and select our materials differently in men and women. The results of the current study did not reveal any significant difference in the bite force displayed by clenchers, bruxers, and normal occlusion subjects. [PERSON] and [PERSON] reported that individuals with clenching and grinding habits have a higher bite force only on incisors, but not on molars. Their explanation was that parafunctional habits are usually performed in non-centric positions when the required muscles of these positions are exercised (which occurs when the bite force is measured in the anterior quadrants) and not in a centric position (which occurs when bite force is measured in the posterior quadrants, as was conducted in our study) [50].