• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.285-296
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• 2010

This study was implemented among 100 students of C College of Public Health who have healthy permanent dentition in order to measure the morphology and sizes of clinical crowns of permanent maxillary molars. The following are conclusions of this study. 1. The cusp height, crown width, crown thickness of clinical crowns appeared to be bilaterally symmetrical. 2. The strong development of the buccal groove showed to be superior in the right first molar. The appearance rate of the buccal pit was high in the right first molar also. 3. The type 4th cusp appeared as 100% in the left and right first molars, and 78%, 75% in the left and right second molars respectively. 4. The distal lingual cusp(DLC) size were bilaterally symmetrical in the type 4th cusp. 5. As for the distance between two cusp tips, it was large between mesial cusp tips in all of the first and second molars at both sides. 6. Development of the Carabelli's cusp was high in both the left and right first molars. 7. The appearance rate of the oblique ridge was 87.0% in the right first molar, 73.0% in the right second molar, 88.0% in the left first molar, and 73.0% in the left second molar. This is considered to be caused by people who have mild dental crown caries in their first molars. 8. The appearance rate of the mesial marginal ridge tubercle(DMRT) was high in both of the left and right first molars. That of the distal tubercle was 16.0% in the right first molar, 26.0% in the right second molar, 14.0% in the left first molar, and 21% in the left second molar.

• The korean journal of orthodontics
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• v.42 no.5
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• pp.235-241
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• 2012

Objective: The purpose of this study was to evaluate the validity of the 3-dimensional (3D) superimposition method of digital models in patients who received treatment with rapid maxillary expansion (RME) and maxillary protraction headgear. Methods: The material consisted of pre- and post-treatment maxillary dental casts and lateral cephalograms of 30 patients, who underwent RME and maxillary protraction headgear treatment. Digital models were superimposed using the palate as a reference area. The movement of the maxillary central incisor and the first molar was measured on superimposed cephalograms and 3D digital models. To determine whether any difference existed between the 2 measuring techniques, intra-class correlation (ICC) and Bland-Altman plots were analyzed. Results: The measurements on the 3D digital models and cephalograms showed a very high correlation in the antero-posterior direction (ICC, 0.956 for central incisor and 0.941 for first molar) and a moderate correlation in the vertical direction (ICC, 0.748 for central incisor and 0.717 for first molar). Conclusions: The 3D model superimposition method using the palate as a reference area is as clinically reliable for assessing antero-posterior tooth movement as cephalometric superimposition, even in cases treated with orthopedic appliances, such as RME and maxillary protraction headgear.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.65-70
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• 1989

The development of the lobe pattern in the human dentition plays a part in the form and function of each individual teeth. In order to determin the morphological categories used to describe the occlusal surfaces of the maxillary and mandibular molars, the variation of the developmental grooves which separate each lobe in the molars was examined and analysed. The obtained conclusions were as follow. 1. Most of the maxillary first molars with more distinct and more developmental grooves than the other molars but in most cases of the third molar, a heart-shaped outline due to poorly developed or abscent distolingual cusp was most frequent and in this case the third molar had the 3 cusps separated by the central developmental groove and the buccal developmental groove. 2. In most cases, the mandibular first molar had the 5-cusp type that the groove patter resembles a Y, the second molar the 4-cusp type arranged in such a way that the buccal and lingual developmental grooves meet the central developmental groove at right angle on the occlusal surface and many instances of the mandibular third molars had the 5-cusp thpe with a+groove pattern which separatess the mesiolingual cusp from the distobuccal cusp and the 4-cusp type with a+groove pattern. 3. The maxillary and mandibular third molar were most variable in the developmental groove.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.375-381
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• 2009

Purpose: Root resection can be a valuable procedure when the tooth in question has a high strategic value. The prognosis of root resection has been well documented in previous studies, but the results focused on the palatal root resection have not been discussed in depth. I represent here the short term effectiveness of palatal root resection of maxillary first molars. Methods: Palatal root resection was performed on maxillary first molars of three patients. All the palatal roots were floating state on the radiographic finding and showed full probing depth and purulent exudation at initial examination. Reduction of palatal cusp and occlusal table was performed concomitantly. Endodontic therapy was completed after root resection. Results: Compromised maxillary first molars were treated successfully by palatal root resection in 3 cases. The mobility of resected tooth was decreased a little bit. The probing pocket depth of remaining buccal roots was not increased compared to initial depth. All the patients satisfied with comfort and cost effective results and the fact they could save their natural teeth. Conclusions: Within the above results, palatal root resection is an effective procedure treating compromised maxillary first molar showing advanced palatal bone loss to root apex with or without pulp involvement when proper case selection is performed.

• The Journal of the Korean dental association
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• v.54 no.2
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• pp.142-148
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• 2016

본 연구의 목적은 특이한 C형 치근과 근관을 가지고 있는 상악 제 1대구치의 근관치료 증례를 콘빔단층촬영을 사용하여 진단 및 치료하였음을 보고하는 것이다. 본 증례에서는 특이적인 해부학적 근관 형태가 콘빔단층촬영을 사용하여 확인되었으며 비외과적 근관치료가 시행되었다. 촬영한 영상에서 모든 치근이 C 형태로 융합되어 있으며 독립적인 4개의 근관을 포함하고 있음이 관찰되었다. C형 근관계의 복잡성을 고려할 때 콘빔단층촬영이 적절한 근관계의 확인과 의원성 손상을 예방하기 위해 유용한 보조적 방법인 것으로 보여진다.

• 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.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.55-62
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• 2016

Objectives: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. Materials and Methods: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. Results: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). Conclusions: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

• The Journal of Korean Academy of Prosthodontics
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• v.14 no.1
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• pp.35-40
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• 1976

The author observed the positional relationship of maxillary cuspid to ala-lacrimal duct line in the 594 Koreans(329 male, 265 female) who had relatively normal teeth arrangement, aged 16 to 70. The relationship of ala-lacrimal duct line to the distal angie of maxilly cuspid of the subjects were classified as follows; Type A : Ala-lacrimal duct line was lotated more medially than the distal angle of maxillary cuspid. Type B : Ala-lacrimal duct line coincided with the distal angle of maxillary cuspid. Type C: Ala-lacrimal duct line was located more distally than the distal angle of maxillary cuspid. The occlusal relationship of the maxillary first molar to the mandibular first molar of the subjects were classified as follows; Group I : Group of neutrocclusion relationship. Group II : Group of distocclusion relationship. Group III : Group of mesiocclusion relationship. The obtained results were as follows; 1) The positional relationship of maxillary cuspid to ala-lacrimal duct line were as follows; (Male) Type A: $68.5%{\pm}1.58m%$, Type B: $22.5%{\pm}2.30m%$, Type C: $9.1%{\pm}\1.58m%$ (Female) Type A : $64.5%{\pm}2.94m%$, Type B: $26.5%{\pm}2.71m%$, TypeC: $8.9%{\pm}1.73m%$ 2) Ala-lacrimal duct line located more distally in group II and group III than group I at the point of the positional relationship of upper and lower first molar. 3) Average distance and standard deviation in type A were as follows; (Male) Right: $2.17mm.{\pm}1.01mm.$ Left: $2.27mm.{\pm}1.02mm.$ (Female) Right: $2.06mm.{\pm}0.70mm.$ Left: $2.24mm.{\pm}0.80mm.$ 4) Average distance and standard deviation in type C were as follows; (Male), Right: $1.47mm.{\pm}0.85mm.$ Left: $1.52mm.{\pm}0.97mm.$ (Female) Right: $1.04mm.{\pm}0.44mm.$ Left: $1.26mm.{\pm}0.89mm.$ The results of 3) and 4) had no significant difference between the male and female.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.4
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• pp.213-220
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• 2023

Background: Third molar extraction is the most commonly performed minor oral surgical procedure in outpatient settings and requires regional anesthesia for pain control. Extraction of the maxillary molars commonly requires both posterior superior alveolar nerve block (PSANB) and greater palatine nerve block (GPNB), depending on the nerve innervations of the subject teeth. We aimed to study the effectiveness of PSANB alone in maxillary third molar (MTM) extraction. Methods: A sample size comprising 100 erupted and semi-erupted MTM was selected and subjected to study for extraction. Under strict aseptic conditions, the patients were subjected to the classical local anesthesia technique of PSANB alone with 2% lignocaine hydrochloride and adrenaline 1:80,000. After a latency period of 10 min, objective assessment of the buccal and palatal mucosa was performed. A numerical rating scale and visual analog scale were used. Results: In the post-latency period of 10 min, the depth of anesthesia obtained in our sample on the buccal side extended from the maxillary tuberosity posteriorly to the mesial of the first premolar (15%), second premolar (41%), and first molar (44%). This inferred that anesthesia was effectively high until the first molars and was less effective further anteriorly due to nerve innervation. The depth of anesthesia on the palatal aspect was up to the first molar (33%), second molar (67%), and lateromedially; 6% of the patients received anesthesia only to the alveolar region, whereas 66% received up to 1.5 cm to the mid-palatal raphe. In 5% of the cases, regional anesthesia was re-administered. An additional 1.8 ml PSANB was required in four patients, and another patient was administered a GPNB in addition to the PSANB during the time of extraction and elevation. Conclusion: The results of our study emphasize that PSANB alone is sufficient for the extraction of MTM in most cases, thereby obviating the need for poorly tolerated palatal injections.

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.165-180
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• 2007

Dental Implants have been proved to be successful prosthetic modality in edentulous patients for 10 years. However, there are few reports on the survival of implant according to location in molar regions. The purpose of this study was to evaluate the $4{\sim}5$ years' cumulative survival rate and the cause of failure of dental implants in different locations for maxillary and mandibular molars. Among the implants placed in molar regions in Gwangju Mir Dental Hospital from Jan. 2001 to Jun. 2002, 473 implants from 166 patients(age range; $26{\sim}75$) were followed and evaluated retrospectively for the causes of failure. We included 417 implants in 126 periodontally compromised patients, 56 implants in 40 periodontal healthy patients, and 205 maxillary and 268 mandibular molar implants. Implant survival rates by various subject factors, surgical factors, fixture factors, and prosthetic factors at each location were compared using Chi-square test and Kaplan-Meier cumulative survival analysis was done for follow-up(FU) periods. The overall failure rate at 5 years was 1O.2%(subject level) and 5.5%(implant level). The overall survival rates of implants during the FU periods were 94.5% with 91.3% in maxillary first molar, 91.1% in maxillary second molar, 99.2% in mandibular first molar and 94,8% in mandibular second molar regions. The survival rates differed significantly between both jaws and among different implant locations(p<0.05), whereas the survival rates of functionally loaded implants were similar in different locations. The survival rates were not different according to gender, age, previous periodontal status, surgery stage, bone graft type, or the prosthetic type. The overall survival rate was low in dental implant of too wide diameter(${\geq}5.75$ mm) and the survival rate was significantly lower for wider implant diameter(p