• Journal of Periodontal and Implant Science
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• 제51권6호
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• pp.398-408
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• 2021

Purpose: In this study, we aimed to evaluate the clinical validity of the modified tunneling technique using minimal soft tissue harvesting and volume-stable collagen matrix in the anterior mandible. Methods: In total, 27 anterior mandibular teeth and palatal donor sites in 17 patients with ≥1 mm of gingival recession (GR) were analyzed before and after root coverage. For the recipient sites, vertical vestibular incisions were made in the interdental area and a subperiosteal tunnel was created with an elevator. After both sides of the marginal gingiva were tied to one another, a prepared connective tissue graft and volume-stable collagen matrix were inserted through the vestibular vertical incision and were fixed with resorbable suture material. The root coverage results of the recipient site were measured at baseline (T₀), 3 weeks (T₃), 12 weeks (T₁₂), and the latest visit (T_l). For palatal donor sites, a free gingival graft from a pre-decided area avoiding the main trunk of the greater palatine artery was harvested using a prefabricated surgical template at a depth of 2 mm after de-epithelization using a rotating bur. In each patient, the clinical and volumetric changes at the donor sites between T₀ and T₃ were measured. Results: During an average follow-up of 14.5 months, teeth with denuded root lengths of 1-3 mm (n=12), 3-6 mm (n=11), and >6 mm (n=2) achieved root coverage of 97.01%±7.65%, 86.70%±5.66%, and 82.53%±1.39%, respectively. Miller classification I (n=12), II (n=10), and III (n=3) teeth showed mean coverage rates of 97.01%±7.65%, 86.91%±5.90%, and 83.19%±1.62%, respectively. At the donor sites, an average defect depth of 1.41 mm (70.5%) recovered in 3 weeks, and the wounds were epithelized completely in all cases. Conclusions: The modified tunneling technique in this study is a promising treatment modality for overcoming GR in the anterior mandible.

• 대한치과교정학회지
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• 제42권5호
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• pp.255-262
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• 2012

Objective: We aimed to compare the retention characteristics of Essix and Hawley retainers. Methods: Adolescents undergoing fixed appliance treatment at 2 centers were recruited for this study. Twenty-two patients (16 women and 6 men) wore Essix retainers (Essix group) while 20 (14 women and 6 men) wore Hawley retainers (Hawley group). The mean retention time was 1 year, and the mean follow-up recall time for both groups was 2 years. Two qualified dental examiners evaluated the blind patient data. Maxillary and mandibular dental casts and lateral cephalograms were analyzed at 4 stages: pretreatment (T1), post-treatment (T2), post-retention (T3), and follow-up (T4). Results: The results revealed that Essix appliances were more efficient in retaining the anterior teeth in the mandible during a 1-year retention period. The irregularity index increased in both arches in both groups after a 2-year post-retention period. The mandibular arch lengths increased during treatment and tended to return to their original value after retention in both groups; however, these changes were statistically significant only in the Hawley group. Cephalometric variables did not show any significant differences. Conclusions: The retention characteristics of both Essix and Hawley retainers are similar.

• 치과방사선
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• 제19권1호
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• pp.163-169
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• 1989

The purpose of this study is to investigate on the clinical and radiographic patterns of residual cyst of the jaw for early diagnosis and treatment. The auther studied 87 cases of residual cyst with regard to age, sex distribution, the site of the lesion and several radiographic features. The results were as follows: 1. The average age was found to be 42.6 years, with a range of 15 to 84 years. The incidence was highest in the third and fourth decades(50.6%) and total 87 cases consist of 47 males and 38 females. 2. The common clinical symptoms were pus discharge, swelling, pain and no symptoms was presented in 5 cases(12.5%). 3. Residual cysts were found to be 46.0% maxillary anterior region, 18.4% maxillary molar region, 17.2% mandibular molar region and to be more common in the maxilla(70.1%) than in the mandible(29.9%) 4. Most of residual cysts were unilocular type(86 cases, 98.8%), showing distinct border(62 cases, 71.3%) with smooth margin(78 cases, 89.7%). 5. The adjacent teeth showed root resorption in 13 cases(14.9%), and root divergence in 16 cases(18.4%). 6. The residual cysts extended to the nasal fossa(22 cases, 22.5%), the maxillary sinus(19 cases, 19.4%) and caused the displacement of the mandibular canal wall (11 cases, 11.2%)

• 대한치과보철학회지
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• 제26권1호
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• pp.63-84
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• 1988

Recently the instantaneous centre concept has been used to understand the biomechanics by which a tissue derangement causes a mechanical derangement in temporomandibular joint. In this study, four male subjects without temporomandibular joint disorder and malocclusion were selected for the determination of the instantaneous centre of rotation (I.C.R) in the mandibular movement. The habitual opening and closing paths were recorded on the sagittal plate by two spring pencils attached on the lower anterior teeth which was designed for this study, and the I.C.R. was calculated by the computer program of Rouleaux's method. Also the computer graphic opening and closing movements of mandible were obtained according to the determined I.C.R. The results obtained from this study were as follows. 1. The instantaneous centres of rotation were not positioned within the condyle in the mandibular opening and closing movement. 2. There was some similarity between the anatomical curvature of the articular emience and the movement pattern of condyle. 3. The opening path and the closing path of the most superior pl)int of the condyle stowed a slight difference. 4. At the early stage of the habitual opening movement, the condyle was moved downward. 5. The opening and closing mandibular movements were simulated by the instantaneous centre of rotation which was determined by the computer program of Rouleaux's method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권5호
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• pp.331-335
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• 2017

Clinical limitations following closed reduction of an intracapsular condylar fracture include a decrease in maximum mouth opening, reduced range of mandibular movements such as protrusion/lateral excursion, and reduced occlusal stability. Anteromedial and inferior displacement of the medial condyle fragment by traction of the lateral pterygoid muscle can induce bone overgrowth due to distraction osteogenesis between the medial and lateral condylar fragments, causing structural changes in the condyle. In addition, when conventional maxillomandibular fixation (MMF) is performed, persistent interdental contact sustains masticatory muscle hyperactivity, leading to a decreased vertical dimension and premature contact of the posterior teeth. To resolve the functional problems of conventional closed reduction, we designed a novel method for closed reduction through protrusive MMF for two weeks. Two patients diagnosed with intracapsular condylar fracture had favorable occlusion after protrusive MMF without premature contact of the posterior teeth. This particular method has two main advantages. First, in the protrusive position, the lateral condylar fragment is moved in the anterior-inferior direction closer to the medial fragment, minimizing bone formation between the two fragments and preventing structural changes. Second, in the protrusive position, posterior disclusion occurs, preventing masticatory muscle hyperactivity and the subsequent gradual decrease in ramus height.

• 대한치과보철학회지
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• 제51권3호
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• pp.199-207
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• 2013

연구 목적: 저작 및 하악 운동시 발생되는 치아접촉은 치열의 보존, 하악의 안정과 보철 수복과정에 있어서 중요하다. 이에 한국인의 20-30대 성인을 대상으로 최대교두감합위에서의 치아접촉점의 위치 및 교합유도양상과 교합유도치의 분포를 분석하여 알아보고자 한다. 연구 대상 및 방법: 29명의 성인을 대상으로 하악의 최대교두감합위에서의 치아접촉점의 위치와 분포 및 전방운동시 교합접촉양상을 shimstock foil (Whaledent, Langenau, Germany), T-Scan III (Tekscan Inc., Boston, MA, USA), polyvinylsiloxane registration material (Genie Bite, Sultan Healthcare, Hackensack, NJ, USA)을 이용하여 측정하였다. 측정시 자세는 직립위로 Frankfurt horizontal plane과 지면이 수평이 되도록 앉게 하였으며 접촉이 재현될 때까지 수 차례 반복한 후 3회씩 측정하였다. 최대교두감합위에서 세가지 방법 간의 통계적 유의성을 비교하기 Fisher's Exact Test (R-General Public License, ver. 2.14.1)를 이용하였고, 전방 운동시 Pearson's Test를 통해 통계 검증하였다(${\alpha}=.05$). 결과: 최대교두감합위에서의 치아 접촉 양상을 shimstock foil, T-Scan III, polyvinylsiloxane registration material로 측정시 전치부, 소구치부, 구치부 모두에서 접촉하는 경우가 대부분이었으며, shimstock 사용시 약51%의 최대교두감합위는 전치부 접촉에서 일어났다. Shimstock foil과 T-Scan III를 사용하여 전방운동 측정시 중절치의 접촉이 가장 많이 일어났다. 결론: 최대교두감합위에서 실제 모든 치아의 접촉이 이루어지지 않는 경우가 있었으며 따라서 구치부에서 전치부를 보호해 주고 있음을 확인할 수 있었다. 또한, 전방운동 시 전치부의 치아접촉은 과도한 구치부의 치아접촉을 방지해 전치부가 구치부를 보호해 주고 있었다. 따라서 교합 재구성 시에는 이러한 상호 보호 교합에 대한 고려가 필요하다.

• 한국치위생학회지
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• 제16권4호
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• pp.525-530
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• 2016

Objectives: The purpose of the study is to investigate remineralization effect according to application cycle of fluoride varnish in preschool children. Methods: The study subjects were fifty six children (92 teeth) having one or more early dental caries lesion. Fluoride varnish was applied to the primary area of maxillary and anterior mandibular teeth with the interval of one month, three months, and six months. Results: Dft index was 3.54 in male and 3.44 in female. The fluorescence loss(${\Delta}F$) value due to early caries lesions showed a significant difference in experiment groups I and II after the application of fluoride varnish, but there was no significant difference in experiment group III. After fluoride varnish application, there was a significant change in experimental group I and III. The maximum fluorescence loss(${\Delta}Fmax$) from early caries lesions showed a significant difference after application of the fluoride varnish in all three experiment groups of I, II, and III(p<0.001). Conclusions: Fluoride varnish should be recommended and applied to the children of high risk caries group in every three months.

• 대한소아치과학회지
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• 제21권2호
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• pp.611-616
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• 1994

A major cause of missing permanent incisors is congenital abscence and extraction because of trauma and pathologic condition. The request for restoration of missing or spaced anterior teeth is common in dental practice. Problems, such as the tilting, drifting, and rotation of teeth adjacent to the space, complicate the restoration of apperance, and a normally simple restorative dental procedure may become difficult. There are two primary treatment alternatives to improving a dentition's irregular and spaced apperance-closing the space by orthodontic means or providing a prosthesis to disguise the space. The treatment choice depends on many variables, but, as a general rule, patients with a normal overbite, overjet, and buccal relationship are better treated by maintaining the sapce and providing a prosthesis, either fixed or removable. This case report presents two cases : Traumatic loss of maxillary right and left central incisors, Extraction of malformed mandibular right central inciosr. The loss of central incisor space was regained by the fixed-removable and fixed orthodontic appliance, and then Maryland bridge was cemented.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.5-12
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• 2012

Purpose : This study was performed to evaluate possible variations in maxillary and mandibular bone texture of normal population using the fractal analysis, particles count, and area fraction in intraoral radiographs. Materials and Methods : Periapical radiographs of patients who had full mouth intraoral radiographs were collected. Regions of interest ($100{\times}100$ pixels) were located between the teeth of the maxillary anterior, premolar, and molar area, as well as the mandibular anterior, premolar, and molar areas. The fractal dimension (FD) was calculated by using the box counting method. The particle count (PC) and area fraction (AF) analyses were also performed. Results : There was no significant difference in the FD values among the different groups of age, gender, upper, and lower jaws. The mean FD value was $1.49{\pm}0.01$. The mean PC ranged from 44 to 54, and the mean AF ranged from 10.92 to 11.85. The values of FD, PC, and AF were significantly correlated with each other except for the upper molar area. Conclusion : According to the results, patients with normal trabecular pattern showed a FD of approximately 1.5. Based on these results, further investigation would be recommended if the FD value of patient significantly differenct from this number, since the alteration of this value indicates microstructural modification of trabecular pattern of the jaws. Additionally, with periapical radiographs, simple and cost-effective, PC and AF could be used to assess the deviation from the normal.

• 대한치과보철학회지
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• 제29권2호
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• pp.295-317
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• 1991

The discrepancy between centric relation and centric occlusion have a great role on the successful prosthodontic and occlusal treatment. This study was performed to investigate the effect of the discrepancy between centric relation and centric occlusion on condylar guidance inclination and Bennett shift (immediate and progressive side shift). Sixteen adults who have physiologically normal occlusion and are free of TMJ dysfunction were selected. The amount of the sagittal CR-CO discrepancy in lower anterior incisor was obtained by Saphon Visi-Trainer. The amount of the CR-CO discrepancy in condylar level was measured on the individualized corrected tomography. Pantronic survey was performed by using a arbitrary hinge axis according to manufacturer's direction. All subjects were divided into two groups, group I (small) and group II (large), according to the amount of CR-CO discrepancy. At first the amount of the CR-CO discrepancy in condylar level between two groups was compared and then the condylar guidance inclination and Bennett shift between two groups were compared and analyzed. The results were as follows; 1. The average CR-CO discrepancy in lower anterior incisors was 0.7mm superoinferiorly, 0.49mm anteroposteriorly, and 0.88 mm in total. The average CR-CO discrepancy in condylar level was 0.43mm. 2. The CR-CO discrepancy measured on teeth level and condylar level were highly correlated (p<0.01). 3. The correlation of the condylar position in the glenoid fossa between two groups was not statistically significant. 4. The large CR-CO discrepancy group showed greater amount of Bennett shift and condylar guidance inclination, but there is no statistical significancy. 5. It seems that the CR-CO discrepancy have greater effect on progressive side shift than other elements of mandibular movements.