Reasearch progress in posterior corneal surface anterior protrusion after the excimer laser corneal refractive surgery / 中华实验眼科杂志

With the mature of techniques and development of equipments in excimer laser corneal refractive surgery,the postoperative complications are decreasing gradually.As the center of cornea become thin after laser in situ keratomileusis (LASIK)and laser subepithelial keratomileusis ( LASEK ),the strength of cornea and the intraocular pressure relatively step down,which can cause cornea anterior protrusion more or less.Because the posterior surface which is not directly affected by surgical process and healing process,so it is usually used to evaluate the protrusion of cornea.As the application of.ophthalmic anterior segment imaging and analysis system,we can get more message of cornea posterior surface.The manifestation,principle and precautionary measures of corneal posterior surface anterior protrusion after the excimer laser corneal refractive surgery were reviewed.

Rapid canine retraction in a Class II bialveolar protrusion case using a lingually extended distraction screw / 대한치과교정학회지

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.