• Imaging Science in Dentistry
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• v.42 no.4
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• pp.219-224
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• 2012

Purpose: This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. Materials and Methods: The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. Results: In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. Conclusion: The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.97-114
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• 1999

The first function of occlusion is mastication. Therefore the functional restoration of occlusal surface is very important. The restoration of occlusal surface is three method as wax bite technique, F.G.P. technique, cone technique. Many dental technician is using compound method. I have knew common point on each teeth during I have waxing up wax pattern. So I studied on the design waxup technique for maxillary molar occlusion. The results of the study were as follows ; 1. The dam wax up method can restore axial contour of teeth very easy and make short working time of wax pattern. 2. The height of dam must be same with cusp of adjacent teeth. 3. Automatically the contour of tooth is appeared if the contour of dam is relationship with cuspid line of adjacent teeth. 4. The height of contour of buccal, lingual surface is formed natural curve to add fluid wax by gravitation. 5. The development groove of Maxillary premolar is appeared V form. 6. The development groove of Maxillary molar is appeared W form. 7. The embrasure is formed to carve around contact point area as round convex. It affects to axial form of tooth. 8. I was knew that the lingual groove and stuart's groove of molar runs parallel with oblique ridge. 9. The buccal groove of molar is formed parallel with direction of teeth arrangement.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.577-585
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• 1995

This study has been performed to determine whether significant differences in the maxillary basal bone pattern exist between skeletal class II malocclusion and normal occlusion. Materials for the skeletal Class III sample consisted of lateral cephalometric roentgenograms and maxillary cast models of 29 adult individuals, 15 males and 14 females. The average age was 19.75 years with a range from 16.4 to 29.1 years. A normal control sample consisted of lateral cephalometric roentgenograms and maxillary cast models of 24 adult individuals, 13 males and 11 females. The average age was 24.25 years with a range from 20.8 to 29.4 years. The results of this study can be summarized and concluded as like follows. 1. In comparing sexual difference of maxillary basal bone morphology in skeletal Class III malocclusion, the following Parameters of males were found to be significally larger than those of females : inter first premolar width, inter molar width, oblique canine height, oblique molar height and maxillary basal bone perimeter. 2. In comparing sexual difference of maxillary basal bone morphology in normal occlusion, the following parameters of males were found to be significally larger than those of females : inter canine width, inter first and second premolar width, inter molar width, oblique canine height and oblique molar height. 3. In comparing maxillary basal bone morphologic difference between skeletal Class III malocclusion md normal occlusion in males, the following parameters were found to be significally larger in normal occlusion : inter canine width, inter canine height, inter molar height, oblique canine height and oblique molar height. 4. In comparing maxillary basal bone morphologic difference between skeletal Class III malocclusion and normal occlusion in females, the following parameters were found to be significally larger in normal occlusion : inter canine height, inter molar height, oblique canine height, oblique molar height and maxillary basal bone perimeter.

• Imaging Science in Dentistry
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• v.45 no.4
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• pp.233-240
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• 2015

Purpose: This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT) Materials and Methods: A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results: Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusion: Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.

• Imaging Science in Dentistry
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• v.40 no.2
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• pp.59-62
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• 2010

Purpose : To investigate and compare the prevalence, size, and location of maxillary sinus septa on panoramic and cone beam computed tomography (CBCT) images. Materials and Methods : Two hundred patients who had taken both panoramic and CBCT images were included. The location of maxillary sinus septa on the panoramic radiographs were recorded and confirmed on the CBCT images. Also the size of septa was measured on the reformatted CBCT images. Results : The prevalence of the patients who had maxillary sinus septa was 51.0% and they showed 179 septa totally. Among them 51.0% of the patients had one septum, 32.4% two septa, 13.7% three, and 2.9% four. The measured heights of the septa were $4.37{\pm}2.87\;mm$, $3.51{\pm}2.47\;mm$, and $3.04{\pm}2.37\;mm$ in the medial, middle, and lateral areas, respectively. It was revealed that 1.0% was located at canine region, 18.0% at first premolar, 25.0% at second premolar, 22.7% at first molar, 19.8% at second molar, and 14.0% at third molar region. Among 213 septa depicted by the panoramic radiographs, only 69.0% were confirmed at the CBCT images. Conclusion : Since various heights and courses of the septa can develop in all parts of the maxillary sinus, adequate assessment of the inner aspect of the maxillary sinus is essential to avoid complications during sinus augmentation procedures. CBCT scanning is the preferred radiographic method for detecting the presence of sinus septa.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.2
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• pp.147-153
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• 2017

This study assessed the association between ectopic eruption of the maxillary first permanent molar and skeletal malocclusion in 5- to 10-year-old children. As subjects, 786 children who attended the Wonkwang University Dental Hospital for orthodontic diagnosis were included. Children with unerupted first permanent molars or fully erupted second permanent molars were excluded. The study group demonstrated ectopic eruption of the maxillary first permanent molar, while the control group did not. Cephalometric radiographs taken between January 2003 and August 2015 were analyzed. Skeletal class III malocclusion was detected in 57.0% of the study group, which differed significantly from that in the control group (p<0.05). The SNA, ANB angles, and A to N-perpendicular distance were significantly smaller, whereas the A-B plane angle and APDI were significantly greater in the study group than in the control group (p<0.05). The SNB and mandibular plane angles were not significantly different between the groups. Thus, maxillary undergrowth is a risk factor for ectopic eruption of the maxillary first permanent molar.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.1
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• pp.30-42
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• 2023

Objectives: While the reliability of immediate implant placement in the maxillary molar has been discussed, its significance is questionable. There have been no guidelines for case selection and surgical technique for successful treatment outcomes of immediate maxillary molar implants. Therefore, in this study, we classified alveolar bone height and socket morphology of the maxillary molar to establish guidelines for immediate implant placement. Materials and Methods: From 2011 to 2019, we retrospectively analyzed 106 patients with 148 immediate implants at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. Inclusion and exclusion criteria were applied, and patient characteristics and treatment results were evaluated clinically and radiologically. Results: A total of 29 tapered, sand-blasted, large-grit, and acid-etched (SLA) surfaces of implants were placed in 26 patients. The mean patient age was 64.88 years. Two implants failed and were reinstalled, resulting in a 93.10% survival rate. Fluctuating marginal bone level changes indicating bone regeneration and bone loss were observed in the first year following installation and remained stable after one year of prosthesis loading, with an average bone loss of 0.01±0.01 mm on the distal side and 0.03±0.03 mm on the mesial side. Conclusion: This clinical study demonstrated the significance of immediate implant placement in maxillary molars as a reliable treatment with a high survival rate using tapered SLA implants. With an accurate approach to immediate implantation, surgical intervention and treatment time can be reduced, resulting in patient satisfaction and comfort.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.27-31
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• 2010

Purpose of study: The purpose of this study was to provide adequate diagnostic guideline for the maxillary sinuses prior to dental implant treatment for edentulous posterior maxillary areas. For this purpose, our procedure involves the estimation of the remaining alveolar bone height, the examination of the anatomical variation in the maxillary sinuses (e.g. sinus septum), and the evaluation of the incidence of preoperative pathological conditions in the maxillary sinuses. Materials and Methods: We selected 189 patients to undergo computerized tomography (CT) in order to account for the posterior maxillary anatomy found in patients of Korean ethnicity. We evaluated the following using Dentascan software: Remaining alveolar bone height, incidence of sinus septum, and rate of preoperative pathologic conditions in the maxillary sinus. The average amount of remaining alveolar bone height was analyzed using the student's t-test for differences according to anatomical site, and the ANOVA was used for the differences according to age group with the level of significance set at 0.05. Results: Alveolar bone heights of upper first premolar, second premolar, first molar, and second molar was 12.24 mm, 10.37 mm, 7.16 mm, and 7.15 mm, respectively with statistical significance (P < 0.05). Incidence of sinus septum as an anatomic variation was 17 out of 189 cases (9.0%). Incidence of mucosal thickening as a pathologic variation was 82 out of 189 cases (43.4%). Conclusion: In treatment planning of posterior maxillary edentulous area of Koreans, the consideration of augmentation surgery for maxillary sinus is required in maxillary molar area before dental implant installation, and preoperative screening of the asymptomatic maxillary sinuses can be regarded as a reasonable preoperative procedure in the planning of dental implant treatment on the posterior maxillary edentulous area.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.2
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• pp.110-115
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• 2012

Ankylosed tooth is defined as 'the discontinuance of normal passive tooth eruption without any mechanical barrier'. Ankylosed tooth treatment is a challenge to dental clinicians. In treatment of maxillary molar ankylosis cases there are risks of oro-antral fistula, displacement of root fragments into the maxillary sinus, as well as the necessity for providing additional sinus bone augmentation for future implant placement. In this study, we suggested a new technique using a piezoelectric device and a lateral side approach to the maxillary sinus leading to the simultaneous removal of the ankylosed maxillary molar and sinus grafting for the purpose of implant site development.

• The korean journal of orthodontics
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• v.46 no.1
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• pp.55-61
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• 2016

Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required.