• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권2호
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• pp.115-131
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• 2000

In the study of craniofacial deformity, it is very important that identifying the factor which can affect the morphology and which is closely related to the morphology, because it can not only improve the comprehension of growth and developmental process but also be applied in growth prediction and treatment modality. Several investigators have already mentioned the characterstics of head posture and airway space in relations to morphologic difference. But it is very meaningful work in clarifying the correlation between morphology, head posture and airway space that observing the change of head posture after morplologic change caused by operation and the change of airway space after same procedure. To investigate above correlation, I selected normal group which is consisted of 43 adults and mandibular prognathism group which is consisted of 47 adults who had been operated by sagittal split ramus osteotomy and were followed up more than 1 year. With their lateral skull radiograghs, reference lines which can evaluate each measuring points and areas without effect of postural change were first determined. And using above reference lines, change of airway space, positional change of tongue and hyoid, change of cranial and cervical angulations were measured. The results obtained from the study were as follows 1. In the change of head posture, the position of tongue and hyoid neighboring to pharynx is more closely related to the reference line of cervical column than to reference line of cranium. 2. After mandibular setback operation, the airway dimension was decreased to 81.6% of preoperative state at 1 month postoperatively and was slightly increased to 89.7% at 1 year postoperatively. 3. Posterior movement of tongue plays important role in decrease of airway dimension and inferior movement of hyoid was closely correlated with posterior movement of tongue. 4. Postoperative anterior movement of mandible, namely, morphologic relapse had correlation with relapse phenomenon of airway dimension. 5. Craniocervical angulation increased postoperatively. Especially in the postoperative early state, there was increased foreward inclination of cervical angulation rather than increase of cranial angulation. But at postoperative 1 year it was observed that cervical inclination was returned to preoperative state and cranial angulation was increased gradually. 6. Increase rate of airway dimension was correlated with the increase of cranial angulation from postoperative 1 month to 1 year. In conclusion, relapse tendency of airway dimension following increase of cranial angulation was found after mandibular setback operation and it is considered that increase of cranial angulation is one of compensatory mechanism in airway maintenance.

• Imaging Science in Dentistry
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• 제37권3호
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• pp.127-131
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• 2007

Purpose: To measure the differences of the splint pin angulation and the position of the planned implant site after conventional tomographic analysis. Materials and Methods: The angulation and the location of the metal splint pin retained in acrylic stent were compared with the corrected angulation and the location of the implant fixture on the 331 tomographic images. Results: The stent pins were located buccal in 40%, lingual in 10% to the corrected implant site after analysis of the conventional tomographic image. The angle and the location of the maxillary splint pin were mainly directed buccal on incisor and canine regions. The angle and the location of the splint pins in premolar and molar regions needed less corrections in both maxilla and mandible. Conclusions: This study demonstrated that the use of tomographs was essential for successful dental implant planning.

• 대한소아치과학회지
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• 제42권1호
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• pp.22-29
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• 2015

본 연구는 최근 12년간 하악 소구치에 발생한 함치성 낭을 가진 환자에 대하여 조대술을 시행한 후 해당 치아의 맹출 양상과 이에 영향을 미칠 수 있는 매복치의 깊이, 경사도, 매복치 치근의 발달 정도 등과의 관계를 평가하였다. 조대술을 시행 한 후 93%의 하악 소구치가 자발적으로 맹출 했으며, 낭종에 이환된 소구치는 이환되지 않은 대조군보다 조대술 후 더 빠르게 맹출 되었고 각도 변화도 더 크게 나타났다(p < 0.05). 이환된 소구치의 치근 발육정도가 낮을수록 맹출 속도가 빠르게 나타났고(p < 0.05), 치축각 변화량은 커지는 경향을 보였으나 통계학적으로 유의하지 않았다(p > 0.05). 대부분의 경우 맹출 속도와 치축각의 변화는 조대술 후 6개월 이내에 나타났다. 이 연구의 결과를 통해 함치성 낭에 이환된 치아의 조대술 후 자발적인 맹출 유도양상에 대한 정보를 제공하여 적절한 진단을 통해 바람직한 치료계획을 수립하는데 도움을 줄 것이다.

• 대한소아치과학회지
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• 제30권3호
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• pp.373-384
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• 2003

사춘기 전 아동에서 흔히 발생되는 함치성 낭을 조대술로 치료한 후 낭에 이환된 치아의 맹출에 영향 미치는 제반요인을 분석하여 이환된 치아의 외과적 또는 교정적 치료 유무의 기준을 마련하고자 본 연구를 시행하였다. 하악 소구치 부위가 함치성 낭으로 이환되어 있으며 조대술 실시 후 8개월 이내에 촬영된 파노라마 관찰사진이 있는 5-12세 아동 총 22명의 증례를 대상으로 하였다. 초진과 재진 시의 관찰기간 동안에 촬영 한 파노라마 사진으로 트레이싱 용지에 필요한 구조물과 치아를 모두 그렸으며 사진 상의 수직, 수평적인 상의 확대 및 축소의 보상을 위하여 초진사진의 제1대구치 치관크기를 기준으로 모든 사진을 표준화시켰다. 각 사진 상에서 낭에 이환된 부위를 실험군, 동일 악궁의 반대측 부위를 대조군으로 설정하여 교두깊이, 각의 크기, 낭의 크기, 교두점 위치지수를 계측하여 측정값을 얻은 후, 각 치아의 발육단계, 이환치아의 경사도, 위치의 변위율, 낭종의 면적 감소량과 치아의 맹출과의 관계를 분석하고자 맹출 속도, 각의 변화율, 낭면적의 감소율, 실험군 내의 조대술 후의 평균 기간(month)을 산정하여 다음의 결론을 얻었다. 낭에 이환된 부위의 영구치의 맹출 속도는 비이환측에 비해 평균 3.5배 빨랐으며 치축의 변화는 평균 $2.7^{\circ}/month$였다. 치근의 성장 단계에 따른 변화에서는 치근의 성장단계가 낮을수록 더욱 빠른 맹출 성향을 보였으며 각의 변화에서도 치근의 성장이 1/4이하 군에서 현저히 높게 나타났으며 낭종내 이환치의 변위에 따른 변화에서는 교두점 위치지수 차이가 30%될 때까지는 맹출 속도가 증가하다가 그 이상에서는 다시 감소하는 경향을 보였다. 낭의 면적 감소율이 $80mm^2/month$이상 감소하는 경우 현저하게 높은 맹출 속도를 보였고 이환된 치아가 근심 변위한 경우 원심 변위한 치아보다 맹출 속도는 낮았지만 각의 변화율은 크게 나타났다. 이환된 치아의 각도 변위가 작을수록 맹출의 속도는 증가하였으며 $15^{\circ}$ 이하의 경우 각도 변화도 높게 나타났다. 조대술 후 대부분의 경우 급격한 맹출 속도와 치축 각의 변화는 6개월 이내에 일어났다.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.316-327
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• 1995

The purpose of this study was to evaluate canal shaping ability and canal angulation change of K-file, straight endosonic K-file and pre curved endosonic K-file. Twenty staight canals and thirty curved canals were selected and divided into five groups according to canals curvature and canal instrumentation method. VI group was prepared by straight endosonic K-file and H1 group by K-file in straigt canals. V2 group was instrumented by straight endosonic K-file, V3 group by pre curved endosonic K-file and H2 group by precurved K-file in curved canals. Radiographs of canals were obtained before and after canal shaping. And postoperative radiographs were compared with preoperative radiographs using superimposition method. The results obtained were as follows ; l. In straight canals, K-file group demonstrated lager percentage of canal enlargement than endosonic K-file group on facial view, but reverse results exhibit on mesial view. 2. In curved canals, precurved K-file group showed largest percentage of canal enlargement, followed by precurved endosonic K-fine group and straight endosonic K-file group was smallest. 3. Percantage of canal enlargement at convex side was greater than at concave side in apical portion of each group. Especially in straight endosonic K-file group, percantage of canal enlargement at convex side and concave side showed sharply difference. 4. In angulation change, the straight endosonic K-file group exhibited the greatest its change, followed by precurved endosonic K-file group and precurved K-file group was the least. Above results suggest that K-file is more effective endodontic instrument than endosonic K-file, and that precurved file is effective for canal shaping in curved canal.

• 대한치과보철학회지
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• 제33권4호
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• pp.769-779
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• 1995

The understanding the nature of 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 repored contact locations with respect to the tooth position. However, there are few report the variation of the occlusal contact point with change in each head position. This study analysed the number of occlusal contact point with change in each head position. 30 subject(male 17, female 13), who ahad natural occlusion and no symptoms of temporomandibular disorder, were selected. The numbers and patterns of tooth contact were recorded by silicone bite registration on stone model at four different head positions with head anguration gauge(from the supine to the upright position). The results obtained were as follows : 1. The numbers of total occlusal contact point on teeth increased to average 25, 29, 35, 42 points as head angulation was changed from the supine to the upright position against the ala-tragus line, and there was significant difference(P<0.05). 2. In the 19 subject(65%)of total 30 subject, the perforated point of the silicone bite indicated that the locus for the prime contact point moved mesially as the head angulation was changed from the supine to the upright position. 3. On the basis of the fact that the anterior occlusal contact point increase as head angulation changed from the supine to the upright position, we could find that the mandibular position is moved anteriorly.

• 대한치과교정학회지
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• 제45권6호
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• pp.289-298
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• 2015

Objective: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs). Methods: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth. Results: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle. Conclusions: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.74-86
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• 1991

The purpose of this study was to evaluate the resulting root canal angulation and shape change after using various enlarging instruments. The mesial canals (120) of extracted human mandibular 1st and 2nd molars were randomly divided into 6 groups; Control, K-type me, Heliapical me, Canal Master me, sonic and ultrasonic instrumentation group. Vertical angulation of each canal was determined by a straight line through the long axis of canal and another straight line through the apical foramen to intersect at the point where the canal began to leave the long axis of the tooth. By recording and comparing the measured angles of the each set of pre-and postinstrumentation. Then, the roots were sectioned horizontally in the apical, middle, coronal thirds and the canal shapes examined, as was the mesiodistal canal diameter as it relates to the external root surface. The results were as follows: 1. Instrumentation using K-type me group resulted in the highest mean change in angulation ($9.900^{\circ}$) (p < 0.005), while Sonic Air MM 3000 group resulted in the least degree of straightening canals ($8.250^{\circ}$) (p < 0.005). 2. Canal Master file group resulted in the best canal shape at the three levels (P < 0.005). 3. Measured minimal mesial root width produced Heliapical me group at the apical 1/3 level, Sonic Air MM 3000 group at the middle 1/3 level, Heliapical me group at the coronal 1/3 level (P < 0.005). 4. Measured minimal distal root width produced Sonic Air MM 3000 group at the apical 1/3 level (P < 0.05), Heliapical me group at the middle 1/3 level (P < 0.005), Canal Master me group at the coronal 1/3 level (P < 0.005). 5. HeIiapical me group produced more increased canal diameter than any other groups (P < 0.005).

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.51.1-51.13
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• 2021

Objectives: This study aimed to evaluate the effect of improper positioning single-peak and multi-peak lights on color change, microhardness of bottom and top, and surface topography of bulk fill and incremental composites after artificial aging for 1 year. Materials and Methods: Bulk fill and incremental composites were cured using multi-peak and single-peak light-emitting diode (LED) following 4 clinical conditions: (1) optimal condition (no angulation or tip displacement), (2) tip-displacement (2 mm), (3) slight tip angulation (α = 20°) and (4) moderate tip angulation (α = 35°). After 1-year of water aging, the specimens were analyzed for color changes (ΔE), Vickers hardness, surface topography (Ra, Rt, and Rv), and scanning electron microscopy. Results: For samples cured by single-peak LED, the improper positioning significantly increases the color change compared to the optimal position regardless of the type of composite (p < 0.001). For multi-peak LED, the type of resin composite and the curing condition displayed a significant effect on ΔE (p < 0.001). For both LEDs, the Vickers hardness and bottom/top ratio of Vickers hardness were affected by the type of composite and the curing condition (p < 0.01). Conclusions: The bulk fill composite presented greater resistance to wear, higher color stability, and better microhardness than the incremental composite when subjected to improper curing. The multi-peak LED improves curing under improper conditions compared to single-peak LED. Prevention of errors when curing composites requires the attention of all personnel involved in the patient's care once the clinical relevance of the appropriate polymerization reflects on reliable long-term outcomes.

• 대한치과교정학회지
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• 제37권2호
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• pp.114-124
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• 2007

파노라마 방사선 사진은 치아 및 주위 조직에 대한 많은 정보를 제공해 주며 교정치료 동안에도 치근의 근원심 경사도나 길이 평가를 위해 흔히 이용되고 있지만 파노라마 방사선 사진에서 보이는 치아의 근원심 각도와 길이는 순(협)설 경사도에 의해 영향을 받는 것으로 알려져 있다. 따라서 본 연구에서는 치아의 근원심 경사도를 정상교합자의 평균 근원심 각도로 유지하면서 순(협)설 경사도만 변화시킬 때 파노라마 방사선 사진에서 각 치아의 근원심 경사도와 길이가 어떻게 변화되는지 알아보고자 하였다. 성인 정상 교합자 30명의 평균 악궁을 기초로 하여 아크릴 모델을 제작한 후 치아를 대신하는. 와이어를 정상 근원심 및 순(협)설 경사도$(I^{\circ})$로 식립하고 여기에 순(협)설 경사도 만 $I-15^P{\circ}$에서 $I+15^{\circ}$까지 $5^{\circ}$씩 변화시켜 파노라마 방사선 사진을 촬영한 후 방사선 사진에 나타난 와이어의 길이와 각도를 각각 계측하였다. 와이어를 정상 근원심 및 순(협)설 각도로 식립했을 때 방사선 사진에서 계측된 길이는 중절치, 측절치, 견치의 경우 실제 길이의 $111%{\sim}117%$의 확대율을 보였고, 소구치와 대구치에서는 $121%{\sim}125%$의 확대율을 보였다. 이 때 근원심 경사도는 그대로 유지하면서 순(협)설 경사도만 $I-15^{\circ}$(순측경사)에서 $I+15^{\circ}$ (설측경사)로 변화시킨 경우 중절치 (p<0.01)와 측절치 (p<0.05)에서만 유의한 확대율 증가를 보였다. 파노라마 방사선 사진에서 치아의 경사도는 대부분 실제 근원심 경사도보다 더 크게 즉 원심경사된 것으로 계측되었고, 이러한 원심경사 경향은 측절치와 견치에서 가장 크게 나타났으며, 제1, 2소구치의 $I+10^{\circ},\;I+15^{\circ}$ 그룹과 제1, 2대구치의 $I+15^{\circ}$ 그룹에서만 실제 근원심 각도보다 더 작게, 즉 근심 경사된 것으로 계측되었다. 또한 순(협)설 경사도의 변화에 따라 파노라마 방사선 사진에서 모든 치아의 근원심 각도가 유의한 변화를 보였는데, 순(협)설 경사도가 작아질수록, 즉 순(협)측 경사될수록 파노라마 방사선 사진에서 더 원심경사되어 나타났다. 따라서 파노라마 방사선 사진에서 중절치와 측절치의 치아 길이와 모든 치아의 근원심 경사도를 평가할 때 치아의 순(협)설 경사도에 따라 영향을 받기 때문에 이를 고려해야 할 것이다.