• The Journal of Advanced Prosthodontics
• /
• 제13권6호
• /
• pp.351-360
• /
• 2021

PURPOSE. The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC). MATERIALS AND METHODS. A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software (P < .05). RESULTS. Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 ㎛ in group CF and 34 ± 6 ㎛ in group PC. RMSE of total adjustments was 61 ± 11 ㎛ in group PC. Quality of occlusal contacts was better in group CF. CONCLUSION. Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.

• 대한치과보철학회지
• /
• 제42권4호
• /
• pp.412-424
• /
• 2004

Statement of problem: Several prosthetic options are available for the restoration of multiple adjacent implants. A passively fitting prosthesis has been considered a prerequisite for the success and maintenance of osseointegration. Passivity is a particular concern with multiple implants because of documented inaccuracies in the casting and soldering process. One way to avoid this problem is to restore the implants individually, however, the restorations of individual adjacent impants requires careful adjustment of interproximal contacts. Purpose: The purpose of this study was to compare the stress distribution pattern and amount surrounding Bicon implants with individual crowns and splinted restorations. Material and method: A photoelastic model of a human partially edentulous left mandible with 3 Bicon implants($4{\times}11mm$) was fabricated. For non-splinted restorations, individual crowns were fabricated on 3 abutments ($4{\times}0.65mm,\;0^{\circ}$, 2.0 mm post, Bicon Inc., Boston, USA) After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal ($8{\mu}m$ shim stock drags without tearing), medium($40{\mu}m)$), and heavy($80{\mu}m$). Splinted 3-unit fixed partial dentures were fabricated and cemented to the model. Changes in stress distribution under simulated non-loaded and loaded conditions(7.5, 15, 30 lb) were analyzed with a circular polaricope. Results: 1. Stresses were distributed around the entire body of fin in Bicon implants. 2. Splinted restorations were useful for distribution of stress around implants especially with higher loads. 3. By increasing the contact tightness between the individually restored three implants, the stress increased in the coronal portion of implants. Conclusions: Ideal adjustment of the contact tightness was important to reduce the stresses around individually restored Bicon implants.

• 치위생과학회지
• /
• 제7권3호
• /
• pp.201-205
• /
• 2007

부산 시내에 소재하는 1곳의 치과의원에 치료를 위해 내원한 111명의 환자와 D대학 치위생과에 재학 중인 학생 105명을 대상으로, 상악 전치부 치은선에 대한 심미 선호도를 조사한 본 연구에서 얻은 결론은 다음과 같다. 두 그룹 간에 상악 전치부 치은선에 대한 심미 선호도 차이는 없었다. 측절치 치은변연의 위치에 대해 측절치 변연이 중절치보다 0.5 낮은 형태를 선호하였다. 중절치 치은선의 형태에서 수평선분의 접촉량이 1/9인 형태를 선호하였다. 인접 접촉점의 길이에서 치관 길이의 1/2이 접촉하는 형태를 선호하였다. 이런 결과는 치과의료기관에서 실제 환자의 치아 및 치은 수복시 이용할 수 있는 심미적 치은선 형태에 관한 기초자료로 도움이 되리라 사료된다.

• Imaging Science in Dentistry
• /
• 제53권3호
• /
• pp.199-207
• /
• 2023

Purpose: The objective of this study was to evaluate the accuracy and effectiveness of an artificial intelligence (AI) program in identifying dental conditions using panoramic radiographs(PRs), as well as to assess the appropriateness of its treatment recommendations. Materials and Methods: PRs from 100 patients(representing 4497 teeth) with known clinical examination findings were randomly selected from a university database. Three dentomaxillofacial radiologists and the Diagnocat AI software evaluated these PRs. The evaluations were focused on various dental conditions and treatments, including canal filling, caries, cast post and core, dental calculus, fillings, furcation lesions, implants, lack of interproximal tooth contact, open margins, overhangs, periapical lesions, periodontal bone loss, short fillings, voids in root fillings, overfillings, pontics, root fragments, impacted teeth, artificial crowns, missing teeth, and healthy teeth. Results: The AI demonstrated almost perfect agreement (exceeding 0.81) in most of the assessments when compared to the ground truth. The sensitivity was very high (above 0.8) for the evaluation of healthy teeth, artificial crowns, dental calculus, missing teeth, fillings, lack of interproximal contact, periodontal bone loss, and implants. However, the sensitivity was low for the assessment of caries, periapical lesions, pontic voids in the root canal, and overhangs. Conclusion: Despite the limitations of this study, the synthesized data suggest that AI-based decision support systems can serve as a valuable tool in detecting dental conditions, when used with PR for clinical dental applications.

• 산업기술연구
• /
• 제36권
• /
• pp.45-48
• /
• 2016

The purpose of this study is to evaluate and compare wettability and setting time of twelve polyvinylsiloxane impression pastes. For comparing the wettability, the contact angle of a water drop on the impression materials was measured. It is important for impression materials to have higher wettability when trying to make impressions of interproximal spaces and gingival crevices. The higher wettability the better the material will flow into these spaces and the more accurate the impression. An ideal impression material will have adequate working time but a fast intraoral setting time. The clinician needs time to inject material into the sulcus, place the impression material into the tray and position it in the mouth, but the material should set rapidly to reduce time in the patient's mouth. It is considered that the results obtained in this study will provide guideline information for the manufacturing of impression materials and for selecting appropriate impression materials.

• Journal of Periodontal and Implant Science
• /
• 제31권3호
• /
• pp.633-640
• /
• 2001

As the public becomes concerned with looking younger and healthy, aesthetic considerations will become more relevant to dental treatment planning. The purpose of this study was to evaluate the relationship between interdental papilla existence and the distance from contact point to interdental alveolar crest in the maxillary anterior dentition of korean. Fifty-nine Korean adult consist of adults. 34 males and 25 females participated in the study. Papilla Index(PI) was recorded. The distance between contact point and interdental alveolar crest was measured by sounding with Williams probe. Measurement were carried out in 257 maxillary anterior interproximal area. The results showed that mean PI was 1.95 and mean distance between contact point and interdental alveolar crest was 5.07mm. The correlation between the papilla index and distance was negative and statistically significant(r=-0.819; p=0.000). A high negative correlation existed between PI and distance from contact point to alveolar crest. When the distance between contact point and alveolar crest was 4mm, the papilla got lost on a half of all cases. When the distance was 5mm, the papilla was present almost 11%. When the distance was 6mm, the papilla was present 4%. When the distance was 7mm or more, the papilla was lost in all cases.

• 대한치과교정학회지
• /
• 제29권6호
• /
• pp.637-648
• /
• 1999

교정 치료 후 이상적인 교합과 양호한 심미적 결과를 얻기 위해서 일반적으로 교정 장치 제거하기 4개월에서 7개월 전에 detailing을 시행한다. 이와 같은 과정을 finishing이라고 하며, 이 과정은 최종적인 양호한 결과를 얻는데 있어서 필수적이다. 일부 교정의는 finishing을 위한 특별한 이론적 근거 및 기준 없이 이 과정을 교정 치료의 마지막 단계에서 시행하면 되는 것으로 여기고 있다. 그러나, 최종적인 양호한 교정 치료 결과를 얻기 위해서는finishing 과정이 총 치료 계획의 부분으로 치료의 초기 단계에서부터 고려되어야만 하며, 교정 장치 제거를 위한 이론적 근거 및 기준에 근거한 finishing을 위한 checklist가 필요하다. 이 checklist는 크게 네 부류로 분류할 수 있다. 즉, 교합 요인, 심미적 요인, 치주적 요인과 습관적 요인으로 분류할 수 있다. 교합 요인에서 점검해야할 요소로는 alignment, marginal ridge discrepancy, interproximal contact, anterior inclination, posterior inclination, overjet, overbite, arch form과 functional occlusion 등이 있다. 심미적 요인에는 gingival form, crown form, crown width과 crown length 등이 있다. 치주적 요인에는 root angulation, bone level 등이 있다. 습관적 요인에는 mouth breathing, tongue position at rest, tongue thrust habit, lip biting, nail biting과 finger sucking 등이 있다.

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

• The Journal of Advanced Prosthodontics
• /
• 제11권2호
• /
• pp.88-94
• /
• 2019

PURPOSE. This study was conducted to investigate patterns of adjacent tooth displacement in the posterior implant with interproximal contact loss (ICL) by 3-D digital superimposition method. MATERIALS AND METHODS. Posterior partially edentulous patients, restored with implant fixed partial prostheses before 2011 and suffered from food impaction of ICL between 2009 and 2011, were included. Two dental casts, at the time of delivery and at the time of food impaction in a same patient, was converted into 3-D digital models through scanning and superimposition was performed to assess chronologic changes of the dentition. Directions of tooth displacement were evaluated and the amount of ICL was calculated. Correlations between the amount of ICL and elapsed time, or between the amount of ICL and age after function, were assessed at a significance level of P<.05. RESULTS. A total number of 13 patients (8 males, 5 females) with a mean age of $65.76{\pm}9.94years$ and 17 areas (4 maxillae, 13 mandibles) were included in this retrospective study. Teeth adjacent to the implant restoration showed complex displacements but characteristic tendency according to the location of the arch. The mean amount of ICL was $0.33{\pm}0.14mm$. Elapsed time from function to ICL was $61.47{\pm}31.27months$. There were no significant differences between the amount of ICL and elapsed time, or age (P>.05). CONCLUSION. Natural teeth showed various directional movements to result in occlusal change in the arch. The 3-D superimposition of chronologic digital models was a helpful method to analyze the changes of dentition and individual tooth displacement adjacent to implant restoration.

• Restorative Dentistry and Endodontics
• /
• 제39권3호
• /
• pp.220-225
• /
• 2014

A fiber-reinforced composite (FRC) fixed prosthesis is an innovative alternative to a traditional metal restoration, as it is a conservative treatment method. This case report demonstrates a detailed procedure for restoring a missing anterior tooth with an FRC. A 44-year-old woman visited our department with an avulsed tooth that had fallen out on the previous day and was completely dry. This tooth was replanted, but it failed after one year. A semi-direct technique was used to fabricate a FRC fixed partial prosthesis for its replacement. The FRC framework and the pontic were fabricated using a duplicated cast model and nanofilled composite resin. Later on, interproximal contact, tooth shape, and shade were adjusted at chairside. This technique not only enables the clinician to replace a missing tooth immediately after extraction for minimizing esthetic problems, but it also decreases both tooth reduction and cost.