Aims: To investigate the differences in morphological characteristics of borderline class III patients who had undergone camouflage orthodontic treatment or orthognathic surgery, and to compare the treatment effects between these two modalities. Materials and Methods: Cephalograms of 25 patients (13 orthodontic, 12 surgical) with class III malocclusion were analyzed. All had a pretreatment ANB angle greater than -5º. Results: Using discriminant analysis, only Holdaway angle was selected to differentiate patients in the pretreatment stage. Seventy-two per cent patients were correctly classified. In the orthodontic group, reverse overjet was corrected by retraction of the lower incisors and downward and backward rotation of the mandible. The surgical group was corrected by setback of the lower anterior dentoalveolus and uprighting of the lower incisors. No difference was found in posttreatment soft tissue measurements between the two groups. Conclusions: (1) Twelve degree for the Holdaway angle can be a guideline in determining the treatment modalities for borderline class III patients, but the preferences of operators and patients are also important. (2) Both therapeutic options should highlight changes in the lower dentoalveolus and lower incisors. (3) Both treatment modalities can achieve satisfactory improvements to the people.

·············································································································································································Excessive gingival display that can be seen when a person smiles can cause non-esthetic problem. This gummy smile is mainly caused by an altered passive eruption, bony maxillary excess, and excessive maxillary lip mobility. Thus far, an altered passive eruption has been successfully treated using esthetic crown lengthening. Recently, an alternative to orthognathic surgery has been proposed for the treatment of a gummy smile. Studies using a lip repositioning procedure have actively been performed. In this report, we present three cases of treatment for excessive gingival display using the modified lip repositioning technique associated with esthetic crown lengthening. 서 론 웃을 때 전반적인 과도한 치은 노출은 심미적 관점에서 문제가 될 수 있다. 이러한 상태는 "gummy smile "로 불 리며, 10.5%[1]에서 29%[2]까지 높은 유병률이 보고되고 있다. 과도한 치은 노출은 남성보다는 여성에게서 더 관찰 되며, 비심미적으로 여겨진다[3]. Gummy smile의 주요 원인으로는 변형된 수동적 맹출[4], 수직적인 상악골 과성장[5], 미소 시 상순의 과활성도[6] 등이 있다. 치아는 악골 내에서 기능적인 교합에 도달할 때까지 능동적 맹출 과정을 거친 후, 부착 기구의 근단 방 향 이동이 발생하는 수동적 맹출 과정을 거치게 된다. 이 러한 수동적 맹출이 완전히 일어나지 않는 경우를 변형된 수동적 맹출이라고 한다[7]. 변형된 수동적 맹출은 과도한 치은노출뿐만 아니라 상악전치부에서 짧은 치관을 야기하 므로, Coslet 등[4]은 각화 치은의 양과 치조정의 위치에 따라 다양한 치주 수술을 선택적으로 활용한 심미적 치관 연장술을 통해 성공적으로 치료할 수 있음을 보고하였다. 또한, 수직적인 상악골 과성장 및 상순의 과활성도에 의한 과도한 치은 노출의 경우에는 입술 재위치술을 통해 예지 성 있는 심미적 개선 효과를 얻을 수 있다[8]. 입술 재위 치술은 Rubenstein과 Kostianovsky[9]에 의해 1973년에 처 음으로 보고되었음에도 불구하고, 최근 들어서야 gummy smile 치료를 위한 악교정 수술의 하나의 대안으로 다시 활발히 연구 되고 있다[10-14]. Silva 등[15]은 상악 순소대 까지 제거하는 기존의 술식의 단점을 보완한 변형된 입술 재위치술을 처음으로 소개하였으며, 이 술식이 보다 덜 침 습적이면서 성공적인 치은 노출 개선효과가 있음을 보고 하였다. 이번 연구에서는 미소 시 과도한 치은 노출을 보이는 환 자에게서 변형된 입술 재위치술과 심미적 치관연장술을 사용하여 심미적 문제점을 개선한 세 가지 증례에 관하여 보고하고자 한다. 증례보고 증례 1 35세 여성 환자로 웃을 때 치은의 과도한 노출이 보기 싫다는 주소로 내원하였다. 전신질환은 없었으며, 1년 전 개인치과에서 치은절제술을 통한 심미적 치관연장술을 시 Case Report

Porous nickel-titanium (Ni-Ti) alloy implants have been previously introduced, and many studies have been performed. Porous Ni-Ti alloys have excellent properties for use in the dental field. Thus, the use of a porous Ni-Ti coating to combine the advantages of Ni-Ti with titanium implants should be considered. The aim of this study was to investigate the tissue response to porous Ni-Ti alloy in vivo. Three 8-mm diameter calvaria bone defects were established in New Zealand rabbits. In the control group, only a collagen membrane was applied to the defect. In experimental group I, the alloy disk was applied to the defect with a bone graft and resorbable membrane. In experimental group II, the alloy disk was placed in the defect covered by a resorbable membrane. After 4 and 8 weeks of healing, the experimental animals were euthanized for specimen preparation. Histomorphometric analysis was performed to quantify new bone formation and connective tissue. The data were analyzed by Kruskal-Wallis and Mann-Whitney U-tests. At 4 and 8 weeks, new bone formation was seen in all groups. The new bone formation was insufficient in the groups with the titanium implants. There was minor inflammation in the experimental groups compared with the control group. In this study, new bone formation and tissue reactions were seen around the porous Ni-Ti alloy. Minor inflammation and insufficient new bone formation were noted in the experimental groups. This meant that the porous Ni-Ti alloy affected the adjacent tissue.

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