• Title/Summary/Keyword: Dental esthetic

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Customized maxillary incisor position relative to dentoskeletal and soft tissue patterns in Chinese women: A retrospective study

  • Zhou, Xueman;Zheng, Yingcheng;Zhang, Zhenzhen;Zhang, Zihan;Wu, Lina;Liu, Jiaqi;Yang, Wenke;Wang, Jun
    • The korean journal of orthodontics
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    • v.52 no.2
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    • pp.150-160
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    • 2022
  • Objective: To provide reliable prediction models based on dentoskeletal and soft tissue variables for customizing maxillary incisor positions and to optimize digitalized orthodontic treatment planning. Methods: This study included 244 Chinese women (age, 18-40 years old) with esthetic profiles after orthodontic treatment with fixed appliances (133 in group I: 1° ≤ The angle between the nasion [N]-A point [A] plane and the N-B point [B] plane [ANB] ≤ 4°; 111 in group II: 4° < ANB ≤ 7°). Dental, skeletal, and soft tissue measurements were performed on lateral cephalograms of the participants. Correlation and multiple linear regression analyses were used to determine the influence of dentoskeletal and soft tissue variables on maxillary incisor position. Results: The ideal anteroposterior position of the maxillary incisor varied between sagittal skeletal patterns. The position of the maxillary incisor correlated with the sagittal discrepancy between the maxilla and the mandible (ANB), protrusion of the midface, nasal tip projection, development of the chin, and inclination of both the maxillary and mandibular incisors. Distance from the maxillary central incisor to nasion-pogonion plane predicted using multiple linear regression analysis was accurate and could be a practical measurement in orthodontic treatment planning. Conclusions: Instead of using an average value or norm, orthodontists should customize a patient's ideal maxillary incisor position using dentoskeletal and soft tissue evaluations.

Full mouth rehabilitation of a patient with excessive worn dentition by increasing vertical dimension of occlusion: a case report (과도한 치아 마모 환자에서 교합수직고경 증가를 동반한 완전구강회복 증례)

  • Jong Seok Lee;Ji Suk Shim;Jae Jun Ryu
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.3
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    • pp.234-244
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    • 2023
  • Tooth wear refers to the loss of dental hard tissue caused by various physiological and pathological causes, and excessive pathological wear can cause complications such as pathological changes in dimensions, occlusal disharmony, loss of function, and aesthetic problems. The cause of tooth wear can be caused by attrition, abrasion, corrosion and abfraction, and it is known to act in a multifactorial etiology in interocclusal activity. In patients with excessive pathological wear, it is important to determine whether or not the vertical dimension of occlusion is reduced, and complete oral rehabilitation should be achieved with the adaptation of the neuromuscular and temporomandibular joint through accurate diagnosis and analysis. The patient in this case was a 63-year-old male patient, who presented discomfort to cold beverage due to severe tooth wear. After analysis of the patient's vertical dimension of occlusion, a full mouth rehabilitation was performed with increasing vertical dimension of occlusion. The goal of treatment was to improve the occlusal plane with the equal-intensity contact of all teeth, harmonious anterior guidance and immediate disclusion of all posterior contacts. After rehabilitation, the patient was satisfied with function and esthetic appearance.

Single-unit fixed restoration using the automated crown shaping artificial intelligence program (자동 치관 형성 인공지능 프로그램을 이용한 단일 고정성 보철물 수복 증례)

  • Eun-Bi Park;Young-Eun Cho
    • Journal of Dental Rehabilitation and Applied Science
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    • v.40 no.3
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    • pp.169-178
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    • 2024
  • Recently, several attempts have been made to integrate AI into the field of dentistry. To overcome the limitations of traditional fixed prosthetic fabrication methods such as CAD-CAM (computer-aided design-computer-aided manufacturing), AI programs are being developed for automated crown fabrication, and various studies are underway to applicate in clinical situation. In these case studies, single-unit fixed prostheses were fabricated using an AI program (Dentbird Crown, Imagoworks Inc, Seoul, Korea) in both the anterior and posterior regions and the fabrication time and accuracy were compared with previously used CAD-CAM method. The first case is a 44-year-old woman who presented for re-fabrication of a zirconia prosthesis due to a prosthesis fracture on the lingual side of the upper right lateral incisor. The second case is a 53-year-old male patient who presented for a crown restoration on an upper left first molar following root canal treatment, where he received a final zirconia restoration. In both cases, the first prosthesis was designed manually using a CAD program, the second prosthesis was designed using AI alone, and the third prosthesis was designed using AI and then modified by CAD program, and the three designs were superimposed to compare suitability. When evaluated after temporary placement, the final prosthesis demonstrates adequate stability, retention and support, resulting in functional and esthetic satisfaction.

A STUDY ON THE COLORS OF THE ANTERIOR PRIMARY RESIN TEETH (유치레진치의 전치부 색조연구)

  • Hyun, Hong-Keun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.4
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    • pp.639-645
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    • 2007
  • Removable or fixed space maintainer could be needed if one or some anterior primary teeth were missing, where resin pontics well-matched to natural primary teeth should be demanded to get an esthetic satisfaction. Resin Natural $Teeth^{TM}$(Nissin dental, Japan) is available currently in Korea, which consists of two shades of colors; type A1 and A2. The purpose of this study is to elucidate the colors of the anterior primary resin teeth and to establish the data to compare those with the natural anterior primary teeth. CIE $L^*a^*b^*s$ were measured each three times labially from 17 sets of maxillary four anterior teeth for type A1 and A2 Resin Natural $Teeth^{TM}$ using ShadeEye $NCC^{TM}$(Shofu, Japan) which is one of spectrophotometers. The data were analysed statistically using Kruskall-Wallis Test and Mann-Whitney U Test. The results were as follows : 1. There were smaller teeth color differences in group A1 than in group A2 when it comes to distributions of ${\Delta}E$, $L^*$ and $b^*$. There were no statistically significant differences of $a^*$ between teeth in the same group(P>0.05). 2. ${\Delta}E$ in group A1 and A2 (maximum ${\Delta}E{\le}1.23$) were very small, which could not be discerned by eyesight. ${\Delta}E$ between mean CIE $L^*a^*b^*s$ of group A1 and A2 was 3.97, which could be discernible by eyesight. 3. Mean measurements of group A1 were $L^*=73.8$, $a^*=-1.8$, $b^*=-4.7$, and those of group A2 were $L^*=75.8$, $a^*=-2.7$, $b^*=-1.4$. It would be recommended that resin teeth compatible to the colors of the natural primary ones needed to be developed by investigating in vivo study.

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Fracture resistance and marginal fidelity of zirconia crown according to the coping design and the cement type (코핑 디자인과 시멘트에 따른 지르코니아 도재관의 파절 저항성)

  • Sim, Hun-Bo;Kim, Yu-Jin;Kim, Min-Jeong;Shin, Mee-Ran;Oh, Sang-Chun
    • The Journal of Korean Academy of Prosthodontics
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    • v.48 no.3
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    • pp.194-201
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    • 2010
  • Purpose: The purpose was to compare the marginal fidelity and the fracture resistance of the zirconia crowns according to the various coping designs with different thicknesses and cement types. Materials and methods: Zirconia copings were designed and fabricated with various thicknesses using the CAD/CAM system (Everest, KaVo Dental GmbH, Biberach., Germany). Eighty zirconia copings were divided into 4 groups (Group I: even 0.3 mm thickness, Group II: 0.3 mm thickness on the buccal surface and the buccal half of occlusal surface and the 0.6 mm thickness on the lingual surface and the lingual half of occlusal surface, Group III: even 0.6 mm thickness, Group IV: 0.6 mm thickness on the buccal surface and the buccal half of occlusal surface and the 1.0 mm thickness on the lingual surface and the lingual half of occlusal surface) of 20. By using a putty index, zirconia crowns with the same size and contour were fabricated. Each group was divided into two subgroups by type of cement: Cavitec$^{(R)}$ (Kerr Co, USA) and Panavia-$F^{(R)}$ (Kuraray Medical Inc, Japan). After the cementation of the crowns with a static load compressor, the marginal fidelity of the zirconia crowns were measured at margins on the buccal, lingual, mesial and distal surfaces, using a microscope of microhardness tester (Matsuzawa, MXT-70, Japan, ${\times}100$). The fracture resistance of each crown was measured using a universal testing machine (Z020, Zwick, Germany) at a crosshead speed of 1 mm/min. The results were analyzed statistically by the two-way ANOVA and oneway ANOVA and Duncan's multiple range test at $\alpha$=.05. Results: Group I and III showed the smallest marginal fidelity, while group II demonstrated the largest value in Cavitec$^{(R)}$ subgroup (P<.05). For fracture resistance, group III and IV were significantly higher than group I and II in Cavitec$^{(R)}$ subgroup (P<.05). The fracture resistances of Panavia-$F^{(R)}$ subgroup were not significantly different among the groups (P>.05). Panavia-$F^{(R)}$ subgroup showed significantly higher fracture resistance than Cavitec$^{(R)}$ subgroup in group I and II (P<.05). Conclusion: Within the limitation of this study, considering fracture resistance or marginal fidelity and esthetics, a functional ceramic substructure design of the coping with slim visible surface can be used for esthetic purposes, or a thick invisible surface to support the veneering ceramic can be used depending on the priority.

Full mouth Rehabilitation with Orthognathic Surgery in Facial Asymmetry Patient : Case Report (안면 비대칭환자의 악교정 수술을 동반한 완전구강회복)

  • Im, So-Min;Shin, Hyoung-Joo;Kim, Dae-Gon;Park, Chan-Jin;Cho, Lee-Ra
    • Journal of Dental Rehabilitation and Applied Science
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    • v.26 no.3
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    • pp.359-371
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    • 2010
  • Facial asymmetry has been found with a higher frequency (70~84%) in skeletal class III malocclusion patients. Anticipating the poor prognosis of prosthesis due to malocclusion, occlusal stability must be obtained by orthodontic treatment. Moreover, orthodontic surgery would be needed in some severe cases for better functional and esthetic results. The orthognathic surgery is performed on one jaw or two jaw depending on the results of facial diagnosis. Genioplasty may change the vertical, horizontal, sagittal position of chin by osteotomy or augmentation using implants, also. This case is about a 24 year-old male patient who visited our clinic to solve the facial asymmetry and mandibular prognathism. Skeletal class III malocclusion, maxillary canting and menton deviation to left by 13 mm were detected. Multiple ill-fitting prostheses, unesthetic maxillary anterior prostheses, and several dental caries were found. After pre-operative orthodontic treatment, Le-Fort I osteotomy, sagittal split ramus osteotomy, genioplasty, right mandibular angle augmentation were done for the correction of jaw relation and asymmetry. By diagnostic wax-up after post-operative orthodontic treatment, maxillary full mouth rehabilitation and mandibular posterior restorations were planned out. For better result, clinical crown lengthening procedure was done on #11, 12 and implant was placed on left mandibular first molar area. The patient was satisfied with the final prostheses. Because of his high caries risk, long-term prognosis will depend on the consistent maintenance of oral hygiene and periodic follow-up.

Shade comparative analysis of natural tooth measured by visual and spectrophotometric methods (육안과 분광 측정기를 이용한 자연 치아의 색조비교분석)

  • Kim, Bum-Suk;Shin, Soo-Yeon;Lee, Jong-Hyuk
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.5
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    • pp.443-454
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    • 2008
  • Statement of problem: A clinically successful color match is one of the important factor to get an esthetic dental restoration. Dental shade guides are commonly used to evaluate tooth color in restorative procedure. But numerous reports have indicated that common shade guides do not provide sufficient spectral coverage of the natural tooth colors. To address issues associated with the shade guide, distinct avenues have been pursued objective spectrophotometric / colorimetric assessment. Purpose: This study compared the accuracy of tooth color selection of spectrophotometer with that of human visual determination. Three main factors were investigated, namely, the effect of light, the individual variation and the experience of the observer. Material and methods: At the first experiment, on ten patients, one operator independently selected the best matching shade to the unrestored maxillary central incisor, using a Vita Classical Shade Guide in the morning, at noon and in the afternoon. The same teeth were measured by means of a reflectance spectrophotometer. At the second experiment, on ten patients, ten operators (5 experts, 5 novices) selected and measured by the same method above at noon. At the third experiment, the results of the second experiment were divided into two groups, expert and novice, and analyzed. Results: 1. There was significant difference between visual and spectrophotometric assessment (mean ${\Delta}E$ values) in experiment 1, 2, 3 (P < .05). 2. There was no significant difference between experts and novices group, when comparing with each visual and spectrophotometric assessment (mean ${\Delta}E$ values). Conclusion: Spectrophotometer could be used to analyze the shade of natural tooth objectively. Thereby, this method offers the potential tominimize considerably the need for corrections or even remakesafter intraoral try-in of restoration. Furthermore, to achieve its advantage, both the shade-matching environment and communication between dentist and technician should be optimized with use of visual and instrumental shade-matching systems.

A STUDY OF INTRAORAL ANATOMIC LANDMARKS OF KOREAN ADULT-UPPER JAW (성인 유치악자 상악골의 악궁과 치열궁의 형태에 관한 조사)

  • Oh, Yu-Ree;Lee, Sung-Bok;Park, Nam-Soo;Choi, Dae-Gyun
    • The Journal of Korean Academy of Prosthodontics
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    • v.33 no.4
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    • pp.753-768
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    • 1995
  • For accurate impression taking of dental patient and esthetic denture treatment of ednetulous patient, measuring between intraoral anatomic landmarks is useful.In this study the subjects selected at a random were two-jundred forty persons with a mean age 22.5(range 21-24) and were taken impression of by irreversible hydrocolloid impression material(Alginate). On the study model made by dental stone, each individual tray was made and final impresion was taken by border moilding. On final model measurings were performed with 3-dimensional measuring device and the values were analyzed by t-test The results is following : ABOUT THE MEASURED VALUES. 1. The width between maxillary right and left canine cusp tip was average 36.44mm(s.d. 2.48), man 36.67mm, woman 35.83mm(p<0.05). 2. The width between labial height of contour of maxillary right and left canine was average 40.08mm(s.d. 2.42), man 40.29mm, woman 39.52mm(p<0.05). 3. The width between mesio-lingual cusps of maxillary first molar was average 43.14mm(s.d. 3.33), man 43.56mm, woman 42.05mm(p<0.05). 4. The width between buccal alveolar ridge on axis of mesiolingual cusp of right and left maxillary first molar was average 64.89mm(s.d. 3.88), man 65.58mm, woman 62.92mm(p<0.05). 5. The width between buccal alveolar ridge on axis of mesiolingual cusp of right and left maxillary second molar was average 68.58mm(s.d. 3.91), man 69.29mm, woman 66.30mm (p<0.05). 6. The width between right and left hamular notch was average 49.80mm(s.d. 3.96), man 50.70mm, woman 48.20mm(p<0.05). 7. The length from labial heigth of contour of maxillary central incisor to center of incisive papilla was average 9.52mm(s.d. 1.18), man 9.46mm, woman 9.63mm(p>0.05). 8. The length from labial heigth of contour of maxillary central incisor to palatine fovea was average 53.27mm(s.d. 2.93), man 53.93mm, woman 52.08mm(p<0.05). 9. The center of incisive papilla ws located posterior to intercanine line at 0.40mm(s.d. 1.16), man 0.51mm, woman 0.11mm(p<0.05). 10. The height from incisal edge of maxillary central incisor to the labial vestibule was average 21.84mm(s.d. 1.38), man 22.01mm, woman 21.00mm(p<0.05). 11. The height from mesiolingual cusp of maxillary first molar to buccalvestible was average 17.45mm(s.d. 1.42), man 17.56mm, woman 17.08mm(p>0.05). 12. The height from hamular notch to standard occlusal plane was average 6.84mm(s.d. 1.06), man 6.91mm, woman 6.70mm(p>0.05). 13. The height from the deepest point of palatal vault to standard occlsalplane was average 19.95 mm(s.d. 2.03), man 20.19mm, woman 19.12mm(p<0.05). ABOUT THE ARCH FORM 1. The arch form was able to classify into four typr by the rate of the measured values. Each arch form distribution was that the 1 group had 32.46% the 2 group 2.19%, the 3 group 52.83%, the 4 group 12.72%. The sexual composition was that in 1 group man had 73.5%, woman 26.5%, in 2 group man had 40.0%, woman 60.0%, in 3 group man had 83.3%, woman 16.7%, and in 4 group man had 55.17%, woman 44.83%. 2. When canine cusp tip was marked as point O, the intersection point between labial height of contour of maxillary central incisor and intermaxillary suture as point A, height of contour of maxillary second molar buccal alveolar ridge as B point, ${\angle}$AOB was measured $133.8^{\circ}$for the 1 group, $133.0^{\circ}$for the 2 group, $132.3^{\circ}$for the 3 group, $128.9^{\circ}$for the 4 group.

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Fracture resistance of zirconia and resin nano ceramic implant abutments according to thickness after thermocycling (지르코니아와 레진나노세라믹 임플란트 지대주의 두께에 따른 열순환 후 파절저항)

  • Lee, Jung-Won;Cha, Hyun-Suk;Lee, Joo-Hee
    • The Journal of Korean Academy of Prosthodontics
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    • v.55 no.2
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    • pp.144-150
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    • 2017
  • Purpose: The aim of this in vitro study is to investigate load bearing capacity of esthetic abutments according to the type of material and wall thickness. Materials and methods: 70 specimens equally divided into seven groups according to their abutment wall thicknesses. The abutments prepared with titanium 0.5 mm wall thickness were used as a control group (Ti-0.5), whereas zirconia abutments and resin nano ceramic abutments with wall thickness 0.5 mm, 0.8 mm and 1.0 mm were prepared as test groups (Zir-0.5, Zir-0.8, Zir-1.0 and RNC-0.5, RNC-0.8, RNC-1.0). All specimens were tested in a universal testing machine to evaluate their resistance to fracture and all of them underwent thermo-cycling before loading test. Mean fracture values of the groups were measured and statistical analyses were made using two-way ANOVA. Results: Zir-1.0 showed the highest mean strength ($2,476.3{\pm}342.0N$) and Zir-0.8 ($1,518{\pm}347.9N$), Ti-0.5 ($1,041.8{\pm}237.2N$), Zir-0.5 ($631.4{\pm}149.0N$) were followed. The strengths of RNC groups were significantly lower compared to other two materials (RNC-1.0 $427.5{\pm}72.1$, RNC-0.8 $297.9{\pm}41.2$) and the strengths of all the test groups decreased as the thickness decreases (P < .01). RNC-0.5 ($127.4{\pm}35.3N$) abutments were weaker than all other groups (P < .05). Conclusion: All tested zirconia abutments have the potential to withstand the physiologic occlusal forces in anterior and posterior regions. In resin nano ceramic abutments, wall thickness more than 0.8 mm showed the possibility of withstanding the occlusal forces in anterior region.

Radiographic evaluation of marginal bone resorption around two types of external hex implants : preliminary study (두 종의 external hex implant의 변연골 흡수에 관한 연구 : 예비연구 (preliminary study))

  • Lee, Ji-Eun;Heo, Seong-Joo;Koak, Jai-Young;Kim, Seong-Kyun;Han, Chong-Hyun
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.2
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    • pp.169-174
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    • 2008
  • Statement of problem: Changes of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. It was proposed that bone-retention elements such as microthreads at the coronal part of implant might help maintain the marginal bone level. Purpose: This study was designed to evaluate the effect of microthread configuration within the marginal coronal portion of the implant fixture at the marginal bone changes after loading around two different external hex implants. Material and methods: Twenty-four patients were included and randomly assigned to treatment with $Br{{\aa}}nemark$ system implants (Group 1, rough-surfaced implants, n=20) and Oneplant system implants (Group 2, rough-surfaced neck with microthreads, n=20). Clinical and radiographic examinations were conducted at baseline (implant loading) and 1 year postloading. Data analysis was performed by the SAS statistical package version 9.1.3 (SAS Institute, Cary, NC, USA) and the final model was calculated by the MIXED procedure (three-level ANCOVA) for marginal bone change of each test group at baseline and 1 year follow-up. Results: Comparing to baseline, significant differences were noted in marginal bone level changes for the 2 groups at 1 year follow-up (P<0.05). Group 1 had a mean crestal bone level changes of $0.83{\pm}0.31mm$; Group 2 had a mean crestal bone level changes of $0.44{\pm}0.36mm$. Rough-surfaced with microthreads implants showed significantly less marginal bone loss than rough surfaced neck without microthread implants. Conclusion: A rough surface with microthreads at the implant was beneficial design to maintain the marginal bone level against functional loading.