• 대한치과보철학회지
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• 제29권1호
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• pp.23-37
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• 1991

The understanding the natureof occlusal tooth contacts of natural dentition is important for correct diagnosis and treatment of diseases developed in stomatognatic system. Several investigator have studied the distribution of tooth contacts in maximum intercuspation and have reported contact locations with respect to the tooth position. Many methods have been clinically applied for the occlusal analysis in the intercuspal position. However, there are few quantative methods. This study analyzed the new software version of the T-Scan system to record and analyze occlusal contact balance in the anterior-posterior and right-left directions. Six time moment statistics and five moment statistics were calculated in the midsagittal and the incisal axes of the occlusal plane. In the present study, informed consent was obtained from 100 subjects with natural dentitions. The results were as follows ; 1. The mean of the dental arch length & width were 48.78, 65.32mm in whole population, 49.09mm, 65.50mm in males, 48.78mm, 64.63mm in females, respectively. 2. The mean of TLR & PLR were 0.193mm(left), 0.311mm(left), respectively. Therefore, the distribution of tooth contacts was bilaterally symmetric. 3. The mean of TFB & PFB were 29.168mm, 29.055mm, and that of LFB & RFB were 29.627mm, 29.587mm, respectively, and the qualitative center of occlusal contacts was the firtst molar. 4. The mean of LL & RL were 31.666mm, 31.377mm, respectively, and the quantitative center of occlusal force was the first molar. 5. The mean of LF & RF were 60.237N, 59.276N, respectively and Left-right moment was 72.491Nmm. Therfore, the distribution of occlusal force was bilaterally balanced.

• International Journal of Oral Biology
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• 제36권4호
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• pp.195-201
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• 2011

Matrix metalloproteinases (MMPs) have been implicated in tissue development and re-modeling. Dynamic morphological changes of tooth germs reflect involvement of these enzymes during odontogenesis. The present study was performed to investigate expression and localization of MMP-2 and MMP-9, which have been known to have type IV collagenase activities, in rat tooth germs at different developmental stages. MMP-2 expression was increased gradually in the tooth germs from cap to crown staged germs at both transcription and translation levels. The localization of this molecule was detected in secretory ameloblasts and preameloblasts. The strong immunoreactivities were occasionally seen along the basement membrane between ameloblasts (or preameloblasts) and odontoblasts (preodontoblasts). However, weak reactivity was detected in odontoblasts and reduced enamel epithelium. The level of MMP-9 expression in the tooth germs was higher in cap stage than in crown staged germs at both transcription and translation levels. They were strongly expressed in both ameloblasts and odontoblasts. Even though reduced enamel epithelium after enamel formation and inner enamel epithelium at the cap stage exhibited weak reactivity, strong reactivity was detected in dental follicles and perifollicular tissues surrounding cap staged germs. These results suggested that MMP-2 may involve degradation of the basement membrane during hard tissue formation, whereas MMP-9 might be involved in remodeling of follicular tissues.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.423-430
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• 2015

PURPOSE. To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth $Ankylos^{(R)}$ implants. MATERIALS AND METHODS. This was a retrospective clinical study that analyzed 450 single $Ankylos^{(R)}$ implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position. RESULTS. The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05). CONCLUSION. The $Ankylos^{(R)}$ implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.

• Journal of Periodontal and Implant Science
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• 제37권3호
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• pp.647-653
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• 2007

Rapid crestal bone resorption following maxillary tooth loss is further accentuated in the posterior regions because of pneumatization and enlargement of the maxillary sinuses. A treatment rationale that allows preservation and augmentation of vertical available bone at the time of posterior maxil-lary tooth extraction may offer numerous therapeutic benefits which are more short courses of ther-apy and no needs of additional surgical augmentation. The present study comprised 3 patients who had 4 posterior maxillary teeth with no evident bone between the tooth apex and sinus floor, as estimated through preoperative radiographic analysis. Sinus floor augmentation at the time of tooth extraction was chosen for the ltreatment of these patients. After the tooth was carefully extracted, the empty alveolus was thoroughly debrided and a trephine approach was performed. Particulated autogenous bone was gently pushed beyond the empty alveolus to elevate the sinus membrane using an osteotome. The distance between bone crest and si-nus floor was radiographically estimated 4 months after the first procedure. Another procedure was then carried out to place the implants of 11 mm length without another augmentation procedure. All implant were clinically stable, with no sign of infection. The presented surgical procedure performed at the time of extraction of posterior maxillary teeth in close proximity to the sinus floor allowed placement of implants of proper length.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권1호
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• pp.15-19
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• 2021

Objectives: The aim of this study was to evaluate correlations between anxiety and preoperative pressure pain assessments and postoperative pain and analgesic requirements in impacted lower third molar tooth surgery. Materials and Methods: This prospective study enrolled 60 patients who underwent impacted lower third molar surgery. The preoperative State-Trait Anxiety Inventory-I (STAI-I), pressure pain threshold, and pressure pain tolerance scores were measured. At 2, 4, 6, 12, and 24 hours, and at 6 days following surgery, the patients scored their pain on the visual analogue scale and recorded their analgesic drug usage. The data were evaluated, and the results were statistically analyzed. Results: Of the 60 patients, 38 were female. Mean age was 24.62±7.42 years. The study found no relationship between preoperative pressure pain assessments and postoperative pain (P>0.05). There was also no relationship observed between preoperative STAI-I scores and postoperative pain (P>0.05). However, there was a positive correlation between operation time and total medication taken (P<0.05). Conclusion: Preoperative pressure pain threshold, pressure pain tolerance, and anxiety level had no significant effects on postoperative pain and analgesic requirements in impacted lower third molar surgery.

• 대한치과교정학회지
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• 제29권5호
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• pp.563-573
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• 1999

본 연구는 치아크기 측정시 버니어 캘리퍼스를 사용한 계측치와 석고모형을 촬영하여 컴퓨터를 사용한 계측치를 서로 비교함으로써 석고모형 분석시 컴퓨터 이용 가능성을 알아보고자 시행되었다. 치아밀집치열 특징을 지니며 모든 치아의 맹출이 완료된 상하악 20조의 석고 모형의 좌측 중절치부터 제 1대구치까지 12개의 치아를 대상으로 하여, 각 치아의 근원심폭경을 버니어 캘리퍼스와 컴퓨터를 이용하여 2주 간격으로 2회 측정하여 실험측정치를 얻은 다음, 측정에 이용된 석고모형을 근원심접촉점 부위에서 개개치아로 분리한 후, 마이크로미터를 이용하여 측정한 표준치와 비교분석하였다. 계측시 오차의 원인을 알아보기 위하여 상하악의 occlusogram을 얻어 각 치아의 접촉점 이탈유무 및 정도를 구하고, TARG (Torque Angulation Reference Guide)를 이용하여 각 치아의 근원심경사도를 계측한 결과 다음과 같은 결론을 얻었다. 1. 2회 측정에 대한 재현도 비교시 버니어 캘리퍼스를 사용한 경우 12 개 치아 중 3개의 치아에서 유의한 차이가 나타났으며 컴퓨터의 경우에는 1 개의 치아에서 차이가 나타났다. 2. 치아크기 계측의 정확도를 알아보기 위하여 표준치와 비교한 결과, 버니어 캘리퍼스를 사용한 경우 12개 중 3개의 치아에서 유의한 차이가 있었으며 컴퓨터의 경우에는 12 개 중 2 개의 치아에서 차이가 나타났다. 3. 버니어 캘리퍼스를 사용한 경우 상악 제 1 대구치는 표준치에 비해 크게, 하악 제 1 대구치는 표준치에 비해 작게 재는 경향을 보였으며 컴퓨터의 경우 상하 제 1 대구치 모두 표준치에 비해 크게 재는 경향을 보였다. 4. 버니어 캘리퍼스로 계측시에는 하악 제 1 대구치가 가장 큰 오차를 보였으며 치아별로 오차정도가 다양하게 나타난 반면, 컴퓨터의 경우 치아별 오차정도의 차이를 보이지 않았다. 5. 접촉점 이탈정도 및 치관의 근원심 경사도와 오차정도의 상관성을 살펴본 결과 버니어 캘리퍼스로 측정한 경우 유의한 상관관계를 보이지 않았으나 컴퓨터로 계측한 경우 약한 순상관관계를 보였다. 이상의 결과는 모형분석을 위한 치아크기 계측시 컴퓨터 이용이 가능함을 시사하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권4호
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• pp.375-380
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• 2007

The purpose of this study is to understand anxiety in patients undergoing third molar extraction and care patients of third molar extraction. The subjects in the study were Sixty-three patients who visited the department of dentistry at Pusan Paik Hospital from May 2006 to September 2006 and who underwent third molar extraction. Patients' anxiety(state anxiety and trait anxiety) to use Spielberger's state-trait anxiety inventory(STAI) were measured. They were asked to fill out STAI question paper immediately before third molar extraction(pre-extraction) and on the day after the extraction(post-extraction). And visual analog scale(VAS) to measure patient's postoperative pain on the day after extraction(postextraction day) was used. Then Differences in anxiety before and after extraction, between men and women, between the first and second extraction, with impacted versus non impacted third molar extraction, between extraction time and anxiety, and between postoperative pain and anxiety were evaluated. The anxiety status of patients undergoing third molar extraction could be quantitatively evaluated using the STAI-KYZ. There were significant difference before and after third molar extraction. Especially women and patients of more severe postoperative pain was more anxious. We need to alleviate patient's anxiety(especially women) and to control postoperative pain throughout the tooth removal process.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권1호
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• pp.3-10
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• 2015

Objectives: We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. Materials and Methods: This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Results: Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; P<0.001). Of the 141 condyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; P<0.001). Conclusion: The increased ratio of angle fractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures.

• Imaging Science in Dentistry
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• 제39권3호
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• pp.109-113
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• 2009

Purpose : The purpose of this study was to examine the inferior expansion of the maxillary sinus floor following maxillary molar extraction. Materials and Methods : Cone beam computed tomographic images of 59 subjects were used to evaluate the height difference of the maxillary sinus floor between extraction sites and contralateral dentate sites. The height of the maxillary sinus floor was defined as the vertical distance to the Frankfort plane from the level of the anterior nasal spine to the most inferior point of the sinus floor. We examined the difference in sinus pneumatization according to the number of missing teeth and the vertical relationship of the molar roots to the sinus floor. Results : The inferior expansion of the maxillary sinus floor was $1.20{\pm}1.86\;mm$ on the maxillary first molar and $1.90{\pm}2.42\;mm$ on the maxillary second molar. Increased expansion was observed in cases where two proximate molars were extracted. There was no significant difference in sinus pneumatization following extraction according to the vertical relationship of the molar roots to the sinus floor. Conclusion : The results of this study confirm that sinus pneumatization occurs following maxillary molar extraction. In situations where pneumatization can affect treatment after molar extraction, three-dimensional radiography should be considered.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권5호
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• pp.343-348
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• 2011

Introduction: Third molar extraction is one of the most common procedures in oral and maxillofacial surgery. The impacted third molar causes many pathological conditions, such as pericoronitis, caries, periodontitis, resorption of adjacent teeth, and cyst or tumors associated with impacted teeth. Extraction is often considered the treatment of choice for impacted lower third molars. On the other hand, imprudent extraction of deeply impacted third molars can cause permanent complications, such as inferior alveolar nerve damage. Therefore, guidelines for the extraction of lower third molars should be set to prevent embarrassing complications. This study examined the indication and current trends of the extracted lower third molars in the dental hospital of a dental college. Materials and Methods: 557 extracted third molars were evaluated at the department of oral and maxillofacial surgery of Yonsei University. The chief complaint, diagnosis, age and degree of impaction were analyzed to determine the tendency for the extraction of asymptomatic lower third molars. Results: The percentage of asymptomatic third molars was 40.8%. In cases of full impacted tooth or full erupted tooth, the percentage of asymptomatic teeth was more than 50% (52.4% and 54.3, respectively). Among those partially impacted teeth, 73.1% of them showed symptoms, such as pain, tenderness and swelling. In terms of age, pericoronitis was evident at a younger age, and dental caries/periodontitis was the main cause of removal in those aged over 50. Twenty nine cases (1.6%) had teeth associated with pathological changes Conclusion: The incidence of pathological changes to the lower third molar was relatively low. Surgical extraction is recommended in cases of partially impacted teeth. In Korea, the incidence of asymptomatic third molar extraction was relatively higher than in European countries. More careful attention would be desirable to consider the risks and benefits of lower third molar extraction.