Manufacture And Experimental Study Of New Type Mirror Oral Retractor With Scale Division

BackgroundOriental ethnic groups tend to like egg-shaped or seed-shaped facial contour, Prominent mandibular angle affect facial aesthetic. More and more mandibular reduction plasty were performed to fulfill the requirements of beauty seekers. With the development of surgical technology, intraoral osteotomy for prominent mandibular angle has become the favorite choice and good exposure is the precondition. Traditional oral retractor is widely used to expose angle of mandible in mandible reduction, but part of the operating range cannot be observed directly, so osteotomy is often performed in half blind State. Amount of bone flap removal is difficult to quantify, the osteotomy range and osteotomy of prediction often depends on the clinical experience of the surgeon. Restricted incision and small intraoral space make the operator unable to keep a relatively clean operating range easily. It increase the operative risks and difficulties, and affect the precise of operating.Objective To introduce the manufacture and animal experiment of a new type oral retractor which can expand operating range of vision and make the operating more precise,.Material and Methods We got a new type oral retractor with mirror and optical fiber through reconstructing a traditional oral retractor. At the frontal part of the retractor, a mirror was made through burnishing and polish. Operator can observe the surgical site at the medial of retractor through the mirror reflection. Scale division was set on the surface of mirror and added douche and suction tube. Eight goats with the body mass of 20-25 kg were randomly divided into two groups:new type retractor group and traditional retractor group with 4 goats in each group. All goats were underwent intral oral bilateral mandible osteotomy using different retractor respectively. Visual condition, bleeding volume, operating time and the difference of flake bone were observed.Results1.In the intraoral mandibular angle osteotomy, we performed the osteotomy reflective visiblely and dominate the procedure by using the new type retractor. Optical fiber provided satisfactory illumination for surgical site. But traditional retractor could just expose mandible restrictedly and the visual range of operator was narrow. Shadowless lamp could not provide enough illumination and usage of headlight was limited by direction and position. The mirror reflection principle and the experimental study show, compare with the traditional retractor, the optic angle and the biggest size of view angle of the new type retractor are both increase about 1-1.5 times.2.The operating time of bilateral mandible osteotomy was shorter in new type retractor group (36.75±2.75min) than traditional retractor group (63.50±2.65min) (P＜0.01).3.The bleeding volume of bilateral mandible osteotomy in traditional retractor group was 30.50±3.69ml,and 18.75±3.30ml in new type retractor group(P＜0.01).4.The precision of bilateral bone flake length in traditional retractor group was 3.92±0.43mm,which was larger than 2.31±0.74mm in new type retractor group (P＜0.05). The difference value of bilateral bone flake width in new type retractor group was 1.53±0.62mm,and 2.79±0.38mm in traditional retractor group (P＜0.05). The error of the length and width of bilateral bone flake in traditional retractor group is 5.91±2.52mm and 3.24±1.83mm respectively, which is larger than 1.99±0.92mm (P＜0.01) and 1.23±0.54mm (P<0.05) in new type retractor group.Conclusion1. The new type retractor was improved from traditional retractor. It's simple in structure and easy to operate. By using the new type retractor,we performed the osteotomy reflective visiablely. Application of scale division quantify the width and length of osteotomy and make the osteotomy more precise. The use of douche and suction device make the operating range clearer,.and the operating will be more convident and efficient.2. Through animal experiment, the new type retractor dominate in visual extent, bleeding volume, accuration and symmetry of bilateral mandible osteotomy and reducing the complications compared with the traditional retractor. The new type retractor can expand the operating range, shorten operating time, make the operating more precise, raise the operating quality and it may be used widely in future.