## 1 Introduction  
Bite force results from the action of the jaw elevator muscles, as modified by jaw biomechanics and reflex mechanisms, and may vary widely in magnitude and direction [1]. The determination of bite force is considered an important parameter in assessing the function and efficacy of dental prostheses and orthodontic treatments and in studying the effect of deformities and pathologies, such as malocclusion and over loading, on the masticatory system [2]. During mastication, loading forces are created by masticatory muscles. The mechanoreceptors of the periodontal ligament control these muscles, and reduced periodontal support may influence their threshold level [3]. The accurate evaluation of a clinical diagnosis of periradicular (PR) conditions or the inflammation of the periodontal ligament around teeth requires a quantifiable method to measure the mechanical pain threshold. A reduction in \"mechanical allodynia\" (pain response to mechanical stimulus) evinces a high sensitivity for detecting PR pain as compared to pulpal pain [4; 5]. The differences between the sensation or pain of a toothed patient and that of an edentulous patient can be due to the lack of the periodontal ligament. When osseointegrated implants were introduced, it was believed that implants would be more susceptible to occlusal overloading due to the lack of a periodontal ligament and its proprioceptive capabilities [6]. These concerns have led to concepts of occlusion on implants, some of which persist today, although no scientific evidence exists regarding the preferred occlusal scheme that will minimize or eliminate complications [6]. In contrast, researchers showed that implant failure has been mainly attributed to peri-implantitis. This biological complication of oral implants is attributed to periodontal pathogens that cause the sub-acute and chronic inflammation of hard and soft tissues surrounding the implants. Therefore, the long-term prognosis depends on the amount of different microorganisms embedded in the biofilm matrix around implants [7]  
Researchers showed that although peri-implant surroundings lack periodontal ligament receptors, there are no differences in the accuracy detection between loads applied to implants and loads applied to natural teeth [8]. [PERSON] et al. studied the suprathreshold discrimination sensitivity of teeth and endosseous implants and found that loads applied to implants and to natural teeth were detected with the same accuracy in both cases [8]. This study and others have concluded that remote mechanoreceptors, that is, receptors which are located apart from of immediate tooth surroundings, might be responsible for the suprathreshold sensitivity of implants and natural teeth [9; 10; 11; 12; 13]. Mechanical pain thresholds in PR tissues can be measured by quantifying the amount of masticatory force that elicits pain. [PERSON] et al. [14] conducted a study in which a digital bite force transducer--bite fork (Occlusal Force-Meter, GM10, [PERSON], Tokyo, Japan)--was placed between posterior teeth of normal healthy control subjects who had to bite on the transducer until they felt pain or discomfort. Because this study recruited subjects with normal PR tissues, the maximal biting force measured represents the normal mechanical pain threshold. The authors concluded that the bite fork has the potential as a quantitative diagnostic aid for measuring mechanical allodynia in patients with natural teeth and implants [14; 15]. Since the maximum bite force is an objective measure of oral function and was demonstrated to be a key determinant of masticatory performance, we used this indicator for evaluating the difference between these two groups of patients [16; 17]. The dental status of an individual might be expected to influence the bite, and fully dentate individuals could be expected to exhibit higher bite force values than individuals with complete dentures, removable partial dentures, or fixed partial dentures [16].