# Physics Foreps in Tooth Extraction--A Systematic Review of Randomized Controlled Trials
## 4 Discussion  
Physics forceps are an instrument that was invented with the primary focus on bringing minimal traumatic extraction. It uses the mechanism of first-class lever along with theprinciple of creep, thereby providing a mechanical advantage to make dental extraction more efficient [13]. It has a beak and a bumper. The beak is attached to one handle of the forceps, which is placed on the palatal or lingual aspect, and the bumper is attached to another handle, which is placed on the mucogingival junction on the facial or buccal aspect, which acts as a fulcrum during extraction [14]. Due to the fulcrum action, shear and compressive forces are produced when the forceps are applied onto the tooth. Shear forces exert on the lingual aspect, whereas a compressive force exerts on the buccal aspect. The bumper expands the force on the bone and surrounding periodontal ligament, thus reducing the incidence of fracture. This principle is called creep [14]. Moreover, the bumper is covered with silicon, which provides a cushioning effect between the bumper and the oral mucosa [8]. When Physics forceps are applied to the tooth surface, the periodontal ligament causes the release of hyaluronidase, which in turn detaches the periodontal attachment to the alveolus and thereby helps in removal from the socket [15; 16] This explains the reason for a less traumatic extraction. A previous report suggests that [17] there is no need to use elevators to raise the mucoperiosteal flap with the use of Physics forceps. An estimation of sample size is very critical for a clinical trial. The underpowered study tends to impart unreliable results. Moreover, among the included studies, the study that has a very large sample size tends to over inflate the outcome result in a systematic review. Assessment of the pre-operative status of the tooth indicated for extraction is of utmost importance. One study [8] included mobile teeth in the selection criteria, although there was no mention about the grade of mobility. This might be one of the confounding factors influencing the results. On assessing the extraction time, studies have shown that Physics forceps reduced the extraction time compared to the conventional forceps due to unidirectional constant force. On the other hand, in the case of conventional forceps, the force is exerted by twisting and rotating, thereby increasing the extraction time [7; 18]. Post-operative pain following the extraction with Physics forceps has been reduced due to a less traumatic extraction. Moreover, complications such as tooth fractures have also been reduced due to a contact unidirectional force exerted. However, it is not possible to arrive at a conclusion with a limited number of studies with poor methodological quality. In evaluating post-operative pain, it would be appropriate to assess the pre-operative pain scores and then to compare it post-operatively, especially in a symptomatic tooth. None of the studies mentioned the pre-operative pain score. This is another confounding factor influencing the results. In a condition such as a tooth with infected and inflamed pulp and periapical tissue, the role of local anesthesia and the mode of injection technique also plays a significant role. The pre-operative status of such conditions affects post-operative pain [19]. None of the studies mentioned the operator who performed the extraction. Most of the studies were performed in the department of oral and maxillofacial surgery, but the studies did not mention whether the extraction was performed by a post-graduate student or by an experienced dentist. Additionally, experience and training is required to use the Physics forceps for extraction. None of the studies commented on the experience of the operator. Discussing the risk of bias, blinding of the operator is not appropriate for this type of study, as the operator will definitely know what kind of forceps were used for extraction. However, it is essential to mention about the assessor bias. None of the studies mentioned assessor bias except one study [7].