• 대한치과교정학회지
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• 제44권5호
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• pp.263-267
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• 2014

Objective: To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT). Methods: Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT. Results: The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05). Conclusions: Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

• Journal of Periodontal and Implant Science
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• 제45권2호
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• pp.46-55
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• 2015

Purpose: This study evaluated the mechanical and structural properties of biphasic calcium phosphate (BCP) blocks processed using a modified extrusion method, and assessed their in vivo effectiveness using a rabbit calvarial defect model. Methods: BCP blocks with three distinct ratios of hydroxyapatite (HA):tricalcium phosphate (TCP) were produced using a modified extrusion method:HA8 (8%:92%), HA48 (48%:52%), and HA80 (80%:20%). The blocks were examined using scanning electron microscopy, X-ray diffractometry, and a universal test machine. Four circular defects 8 mm in diameter were made in 12 rabbits. One defect in each animal served as a control, and the other three defects received the BCP blocks. The rabbits were sacrificed at either two weeks (n=6) or eight weeks (n=6) postoperatively. Results: The pore size, porosity, and compressive strength of the three types of bone block were $140-170{\mu}m$, >70%, and 4-9 MPa, respectively. Histologic and histomorphometric observations revealed that the augmented space was well maintained, but limited bone formation was observed around the defect base and defect margins. No significant differences were found in the amount of new bone formation, graft material resorption, or bone infiltration among the three types of BCP block at either of the postoperative healing points. Conclusions: Block bone substitutes with three distinct compositions (i.e., HA:TCP ratios) processed by a modified extrusion method exhibited limited osteoconductive potency, but excellent space-maintaining capability. Further investigations are required to improve the processing method.

• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.733-742
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• 2007

Bone morphogenetic proteins have been shown to possess significant osteoinSductive potential, but in order to take advantage of this effect for tissue engineering, carrier systems are essential. Successful carrier systems must enable vascular and cellular invasion, allowing BMP to act as a differentiation factor. The carrier should be reproducible, non-immunogenic, moldable, and space-providing, to define the contours of the resulting bone. The purpose of this study was to review available literature, in comparing various carriers of BMP on rat calvarial defect model. The following conclusions were deduced. 1. Bone regeneration of ACS/BMP, ${\beta}-TCP/BMP$, FFSS/BMP, $FFSS/{\beta}-TCP/BMP$, MBCP/BMP group were significantly greater than the control groups. 2. Bone density in the ACS/BMP group was greater than that in ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$ carrier group. 3. Bone regeneration in FFSS/BMP group was less than in ACS/BMP, ${\beta}-TCP/BMP$, MBCP/BMP group. However, New bone area of $FFSS/{\beta}-TCP/BMP$ carrier group were more greater than that of FFSS/BMP group. ACS, ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$, MBCP were used for carrier of BMP. However, an ideal carrier which was reproducible, non-immunogenic, moldable, and space-providing did not exist. Therefore, further investigation are required in developing a new carrier system.

• Journal of Periodontal and Implant Science
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• 제37권3호
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• pp.465-478
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• 2007

Various periodontal barrier membranes used in many clinical and experimental fields, and many recent studies of membranes have reported good results. To improve clinical results, selection of barrier membranes is an important factor. So, we need not only to evaluate various barrier mem-branes, but also to understand the property of barrier membranes appropriate to defect characteristics. For this purpose, this study reviewed available literature, evaluated comparable experimental models, and compared various barrier membranes. From above mentioned methods, the following conclusions are deduced. 1. In i-wall periodontal defect models, new bone formation showed a consistent result, almost 30% of the defect size. New cementum formations measured mostly 40% of the defect size, but showed more variations than new bone formations. This seems to be resulted form difference in experimental methods, so standardization in experimental methods is needed for future studies. 2. Application PLGA barrier membrane to periodontal defect demonstrated improved healing in new bone and new cementum. 3. There was a minimal periodontal regeneration with calcium sulfate barrier membrane only. But, there was better healing pattern in combination of calcium sulfate membrane with bone graft material, such as DFDBA, 4. There was no significant difference between the experimental group that used chitosan mem-brane only and the control group. But, in combination with bone graft material for space maintanence, periodontal regeneration was improved. Overall, Space maintenance is a critical factor for Guided tissue regeneration using barrier membranes. Also, a barrier membrane itself that has difficulty in maintaining space, achieved better result when used with graft material.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.205-221
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• 1998

The present study invetigates the effects of root planing only(control group), DFDBA alone(test group 1) and combined use of DFDB and Dura mater(test group 2) in dehiscence defects in dogs. The results of 8weeks post-surgery by histological comparison between the three groups are as follows. 1. The contol group showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 2. The test group 1 showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 3. The test group 2 showed significant amount of the new cementum and new bone. 4. Both control and test groups healed without any observable root resorption and ankylosis. The above the results suggest that the use of resorbable Dura mater only does not improve the regeneration of new bone and periodontal ligament due to difficulties of space making, but the combined use with DFDB may be more effective.

• 치과방사선
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• 제8권1호
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• pp.5-9
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• 1978

The purpose of this study is to investigate the effect of dental restorations on the periodontal and periapical tissues. The author examined 620 cases of amalgam, 390 cases of gold inlay, 422 cases of crown and 644 cases of bridge through the standard intraoral films being appended in the charts that had been kept at the Dept. of Oral Diagnosis in Seoul National University Hospital. This study obtained the following results; 1. The restorations of amalgam, gold inlay crown and bridge were found more frequently in female than in male. 2. The restorations of amalgam, gold inlay and crown were found more numerously in mandibular teeth than in maxillary teeth in both sexes. But in the case of crown, the fact is quite the reverse especially in anterior teeth. 3. On the contrary, in the case of bridge, the restorations of bridge were much more distributed in the maxillary teeth than in the mandibular teeth. 4. Roentgenographic changes of periodontal tissues whose teeth were treated with any type of four restorations were periodontal space widening, lamina dura discontinuity and periapical lesion in the order described in both sexes. 5. On the occasion of between amalgam and gold inlay or between crown and bridge, the differences of periodontal changes were of no consequence. On the other hand, the differences of periodontal changes were apparant between the group of amalgam & gold inlay and the group of crown & bridge.

• 대한치과의사협회지
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• 제22권11호통권186호
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• pp.961-971
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• 1984

The purpose of this study was designed to evaluate the existence of the junctional epithelia on the tooth surface in periodontal pocket, and what were the morphologic differences between the junctional epithelia on the healthy and advanced periodontitis tooth. Fifteen premolar teeth from patients of Yon Sei University, Dental Infirmary were selected for this study. After extration, the teeth were prepared and examined in Scanning electro microscope. The results were as follows. 1. The junctional epithelia from healthy tooth surface were irreguraly round, oval, polygonal and slightly elongated while those from periodontal pocket were so elongated that difficult to distinguished the individual cell boundary. 2. There were a lot of round space so called 'HOLE or WHORL' which seemed tunnel in periodontal pocket with advanced periodontitis. 3. Microvilli were going to destructed and disappeared on surfaces of junctional epithelia in periodontal pocket with advanced periodontitis. 4. There were a lot of Filopodia on Junctional epithelia from healthy surfaces. %. Junctional epithelia from periodontal pocket with advanced periodontitis contained more inflammatory cells than healthy junctional epithelia did.

• 대한심미치과학회지
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• 제10권1호
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• pp.30-45
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• 2001

In recent years, clinicians' and dentists' esthetic demands in dentistry have increased rapidly. The ultimate goal in modern restorative dentistry is to achieve "white" and "pink" esthetics in the esthetically important zones. Therefore, modern esthetic dentistry involves not only the restoration of lost teeth and their associated hard tissues, but increasingly the management and reconstruction of the encasing gingiva with adequate surgical techniques. Interdental space are filled by interdental papilla in the healthy gingiva, preventing plaque deposition and protecting periodontal tissue from infection. This also inhibits impaction of food remnants and whistling through the teeth during speech. These functional aspects are obviously important, but esthetic aspects are important as well. Complete and predictable restoration of lost interdental papillae remains one of the biggest challenges in periodontal reconstructive surgery. One of the most challenging and least predictable problems is the reconstruction of the lost interdental papilla. The interdental papilla, as a structure with minor blood supply, was left more or less untouched by clinicians. Most of the reconstructive techniques to rebuild lost interdental papillae focus on the maxillary anterior region, where esthetic defects appear interproximally as "black triangle". Causes for interdental tissue loss are, for example, commom periodontal diseases, tooth extraction, excessive surgical periodontal treatment, and localized progressive gingiva and periodontal diseases. If an interdental papilla is absent because of a diastema, orthodontic closure is the treatment of choice. "Creeping" papilla formation has been described by closing the interdental space and creating a contact area. In certain cases this formation can also be achieved with appropriate restorative techniques and alteration of the mesial contours of the adjacent teeth. The presence of an interdental papilla depends on the distance between the crest of bone and the interproximal contact point, allowing it to fill interdental spaces with soft tissue by altering the mesial contours of the adjacent teeth and positioning the contact point more apically. The interdental tissue can also be conditioned with the use of provisional crowns prior to the definitive restoration. If all other procedures are contraindicated or fail, prosthetic solutions have to be considered as the last possibility to rebuild lost interdental papillae. Interdental spaces can be filled using pink-colored resin or porcelain, and the use of a removable gingival mask might be the last opportunity to hide severe tissue defects.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.635-645
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• 1993

This study was perfomed to investigate the prosthodontic and periodontal status of the abutment teeth in distally extending bridges(DEBs) (78 cases) and removable partial dentures(RPDs) (43 cases) for 122 patients (55 males and 57 females) visiting department of Periodontology, Seoul National University Hospital. The average wearing periods were 67.8 months for DEBs and 66.4 months for RPDs. 38.4% of the patients in DEBs and 35.9% in RPDs complainted of chewing discomfort and 22.6% and 24.4% were not chewing on the prosthodontically - treated sides, respectively. In DEBs, when the restoration for 2nd molar supported by 1st molar & 2nd premolar was grouped to type 1, 1st molar supported by 1st & 2nd premolars was type 2, and 1st & 2nd molars supported by 1st & 2nd premolars was type 3, there was a significant differences only in the tooth mobility score among clinical parameters (type 2>type 1>type 3). In RPDs, when bilateral free-end case was grouped to type 1, and unilateral case was type 2, there was a significant difference in the Gingival index (type 1>type 2). In DEBs, 62.8% of restoration were overcontoured, 72% had interproximal space closures, 30.5% overextended pontics and 86.6% overhanging margins. In RPDs, 24.4% of the restorations were overcontoured, 45.5% had interproxinal space closures and 58.3% overhanging margins. From these results of this study, periodontal problems caused by prosthodontic defects were considered to be contributing factors in chewing discomfort.

• 대한치과교정학회지
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• 제32권6호
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• pp.455-466
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• 2002

본 연구의 목적은 periodontal distraction을 통해 급속 견인된 치아의 치조골과 치주인대에서 일어나는 변화를 조직학적으로 관찰하고, 치주조직이 정상적으로 재생될 수 있는지를 규명하는 것이다. 4 마리의 성견을 대상으로 하여, 좌우 상악 제2소구치를 발치 후에 상악 제1소구치 원심측 치간골에 홈을 주는 치조골 수술을 통해 골 저항을 약화시키고 제1소구치와 제3소구치에 periodontal distraction 장치를 장착하였다. 장치는 0.225mm씩, 하루에 2회 활성화시키며 상악 제1소구치를 발치와 공간으로 급속 견인하였다. 치아의 급속 견인은 5 일, 10 일, 20 일간 시행하였으며, 20 일간 견인한 대상에서는 2 주, 4 주, 8 주 후까지 유지기간을 두었다. 20 일간의 periodontal distraction을 통해 상악 제1소구치는 평균 5.02mm 원심 이동하였고, 고정원인 제3소구치는 0.58mm 근심 이동하였다. 조직학적 검사에서 distraction된 치주인대 공간에서는 골 재생과 개조가 빠르게 일어나, 견인 10일에 유골조직이 치아의 견인방향에 평행하게 생성되었고, 새로운 골 조직의 형성과 골 개조를 통한 골 성숙은 periodontal distraction 방향을 따라 활발히 진행되었으며, 이는 다른 골의 distraction osteogenesis에서 나타나는 결과와 비슷하였다. 급속 견인된 치아의 치주인대는 상당히 넓게 나타났고, 교원섬유와 치아간의 정상 관계는 급속 견인이 끝난 후 2주에 나타나기 시작하여 8주에 거의 회복되었다. 그러나, 치주인대의 골 쪽에서는 치아 급속 견인 후 8주까지도 새로운 골이 계속 형성되고 있었고, 교원섬유속이나 Sharpey 섬유는 보이지 않았다. 고정원으로 이용된 치아 주위의 조직반응은 통상적인 교정치료에서와 같이 압박 측에서의 골 흡수와 신장 측에서의 골 형성 소견을 나타냈다. 이상의 결과로 볼 때, periodontal distraction을 통한 치아의 급속 견인 시, 치주인대 조직은 잘 반응하여 치주조직의 재생이 활발히 일어남을 알 수 있었다.