• Imaging Science in Dentistry
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• 제52권1호
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• pp.75-82
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• 2022

Purpose: This cross-sectional study evaluated and categorized the tomographic sagittal root position (SRP) of the maxillary anterior teeth in a Brazilian population. Materials and Methods: Cone-beam computed tomographic scans of 420 maxillary anterior teeth of 70 patients (35 men and 35 women, mean age 25.2±5.9 years) were evaluated. The SRP was classified as class I, II, III, or IV. In class I, the root is positioned against the buccal cortical plate; in class II, the root is centered in the middle of the alveolar housing; in class III, the root is positioned against the palatal cortical plate; and in class IV, at least two-thirds of the root engage both the buccal and palatal cortical plates. Results: In total, 274 teeth (65.2%) were class I, 39 (9.3%) were class II, 3 (0.7%) were class III, and 104 (24.8%) were class IV. The frequency distribution over the teeth groups was different from the overall analysis. Important differences were found in the frequencies of classes I, II, and IV compared to other populations. Sex was not associated with the SRP classes (P=0.307). Age distribution was significantly different over the classes (P=0.004). Conclusion: The findings of this study on the distribution of SRP classes among the Brazilian population compared to other populations demonstrate that the SRP should be analyzed on a case-by-case basis for an accurate treatment plan in the maxillary anterior area.

• Journal of Periodontal and Implant Science
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• 제52권2호
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• pp.170-180
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• 2022

Purpose: This study was conducted to assess the effect of hard and/or soft tissue grafting on immediate implants in a preclinical model. Methods: In 5 mongrel dogs, the distal roots of P2 and P3 were extracted from the maxilla (4 sites in each animal), and immediate implant placement was performed. Each site was randomly assigned to 1 of the following 4 groups: i) gap filling with guided bone regeneration (the GBR group), ii) subepithelial connective tissue grafting (the SCTG group), iii) GBR and SCTG (the GBR/SCTG group), and iv) no further treatment (control). Non-submerged healing was provided for 4 months. Histological and histomorphometric analyses were performed. Results: Peri-implant tissue height and thickness favored the SCTG group (height of periimplant mucosa: 1.14 mm; tissue thickness at the implant shoulder and ±1 mm from the shoulder: 1.14 mm, 0.78 mm, and 1.57 mm, respectively; median value) over the other groups. Bone grafting was not effective at the level of the implant shoulder and on the coronal level of the shoulder. In addition, simultaneous soft and hard tissue augmentation (the GBR/SCTG group) led to a less favorable tissue contour compared to GBR or SCTG alone (height of periimplant mucosa: 3.06 mm; thickness of peri-implant mucosa at the implant shoulder and ±1 mm from the shoulder: 0.72 mm, 0.3 mm, and 1.09 mm, respectively). Conclusion: SCTG tended to have positive effects on the thickness and height of the periimplant mucosa in immediate implant placement. However, simultaneous soft and hard tissue augmentation might not allow a satisfactory tissue contour in cases where the relationship between implant position and neighboring bone housing is unfavorable.

• 대한치과교정학회지
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• 제50권4호
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• pp.278-289
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• 2020

Orthodontic treatment of posterior bite collapse due to early loss of molars and the consequent drift of adjacent teeth is complicated. When the posterior bite collapse occurs in patients with facial asymmetry, both transverse and vertical compensation are necessary for camouflage orthodontic treatment. In such cases, posterior maxillary segmental osteotomy (PMSO) can be an effective alternative procedure that simplifies the orthodontic treatment and shows long-term stability through dental compensation within the alveolar bone housing. This case report aimed to describe the orthodontic treatment of maxillary occlusal plane canting caused by severely extruded maxillary teeth in a patient with skeletal facial asymmetry that was corrected with PMSO along with protraction of the lower second molar to replace the space of the extracted first molar. The treatment duration was 18 months, and stable results were obtained after 2 years of retention.

• 구강회복응용과학지
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• 제36권2호
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• pp.88-94
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• 2020

목적: 본 연구는 한국인에서 상악 전치의 치근 위치를 시상면에서 분석하고, 분류에 따른 빈도를 보고함으로써 즉시 식립 임플란트를 위한 방사선학적 자료를 수집하기 위함이다. 연구 재료 및 방법: 콘빔형 전산화단층영상(cone-beam CT)을 촬영한 환자 중 연구 기준에 적합한 120명(남성 60명, 여성 60명)을 대상으로 후향적 분석을 시행하였다. 축의 방향설정을 시행한 후에, 상악 전치부 치아와 치조골 사이의 관계에 대한 시상 치근 위치를 분석하였다. 치근이 치조골의 협측, 중앙, 구개측으로 위치한 경우 각각 Class I, II, III로 분류하였으며, 치근이 협측과 구개측 모두에서 피질골판에 2/3 이상 닿아있는 경우에는 Class IV로 하였다. 다음으로, 치아의 장축과 치조골의 장축 사이의 각도를 측정하였다. 기술적 분석 및 Kruskal-Wallis 분석을 시행하였으며, 치아의 위치 및 분류에 따른 시상각을 비교하였다. 결과: 상악 전치부의 시상 치근 위치에 대한 빈도분석 결과, Class I은 81.1%, Class II는 10.3%, Class III는 1.9%, 그리고 Class IV는 6.7%로 나타났다. 상악 전치부의 77.5%에서 시상각이 20도 이하로 나타났다. 그러나 견치의 경우, 42.7%에서 20도 이상의 시상각을 보였다. 분류에 따라서는 Class I (16.19)에서 Class II (8.72) 및 Class III (9.93)에 비해 통계학적으로 유의하게 높은 시상각을 보였으며, Class IV (3.79)에서 낮았다. 결론: 본 제한된 연구의 결과를 근거로, 상악 전치의 치근은 일반적으로 협측 치조골에 가깝게 위치하고 있으나, 일부 치아는 매우 얇은 치조골을 가지고 있으며, 30도 이상의 큰 시상각을 보였다. 따라서 적절한 치과 임플란트 치료 계획 수립을 위해 시상 치근 위치 및 시상각에 대한 cone-beam CT 분석이 필요할 것이다.

• 대한치과교정학회지
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• 제51권4호
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• pp.250-259
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• 2021

Objective: The aim of this study was to compare the differences in mandibular posterior anatomic limit (MPAL) distances stratified by vertical patterns in patients with skeletal Class III malocclusion by using cone-beam computed tomography (CBCT). Methods: CBCT images of 48 patients with skeletal Class III malocclusion (mean age, 22.8 ± 3.1 years) categorized according to the vertical patterns (hypodivergent, normodivergent, and hyperdivergent; n = 16 per group) were analyzed. While parallel to the posterior occlusal line, the shortest linear distances from the distal root of the mandibular second molar to the inner cortex of the mandibular body were measured at depths of 4, 6, and 8 mm from the cementoenamel junction. MPAL distances were compared between the three groups, and their correlations were analyzed. Results: The mean ages, sex distribution, asymmetry, and crowding in the three groups showed no significant differences. MPAL distance was significantly longer in male (3.8 ± 2.6 mm) than in female (1.8 ± 1.2 mm) at the 8-mm root level. At all root levels, MPAL distances were significantly different in the hypodivergent and hyperdivergent groups (p < 0.001) and between the normodivergent and hyperdivergent groups (p < 0.01). MPAL distances were the shortest in the hyperdivergent group. The mandibular plane angle highly correlated with MPAL distances at all root levels (p < 0.01). Conclusions: MPAL distances were the shortest in patients with hyperdivergent patterns and showed a decreasing tendency as the mandibular plane angle increased. MPAL distances were significantly shorter (~3.16 mm) at the 8-mm root level.