• The Journal of the Korean dental association
• /
• v.57 no.8
• /
• pp.474-479
• /
• 2019

The purpose of the pulp treatment is to make the function of the primary molar in the oral cavity possible for as long as possible until the exfoliation of the tooth or the development of the occlusion is as long as possible. The pulpectomy is a relatively common procedure for the pediatric dentist in the clinic with dental care of the children nowadays. Primary molar is morphologically more susceptible to dental caries than permanent tooth, and the dental pulp treatment is frequently performed. Furthermore, unlike permanent teeth, the root canal has a large degree of curvature and morphological diversity and complexity, careful consideration is needed. Therefore, it is very important to comprehensively understand the morphological characteristics and diversity of the root and root canals for the successful pulp treatment of the primary molars.

• Journal of Oral Medicine and Pain
• /
• v.13 no.1
• /
• pp.13-21
• /
• 1988

The author studied the vertical height of tooth crown and the amounts of alveolar bone resorption with age. All 84 subjects(44 male, 40female) who visited Dental hospital of Wonkwang University with no history of sever periodontal disease and no experience of periodontal surgery. 84 subject were divided into 3 groups by age, that is, group I(28-32yrs), group II(38-42yrs), and group III(48-52yrs). Informal radiogram with bite wing film(horizontal angulation : $0^{\circ}$, vertical angulation : $+5^{\circ}~+10^{\circ}$) were taken on premolar and molar area. The distances from cusp tip to cementoenamel junction (vertical height of tooth crown) and from cementoenamel junction alveolar crest(amount of alveolar bone resorption) were measured, and then recorded data from 946 teeth were statistically analysed. This study was undertaken to obtain the data for age estimation by the changes of tooth crown height and alveolar bone resorption in the point of forensic odontology. The obtained results were as follows : 1. The average crown height of mandibular right 1st. molar was 7.1mm in group I, 6.7mm in group II, and 6.6mm group III, and the average amount of alveolar bone resorption on mandibular right 1st. molar were 1.8mm in group I, 2.5mm in group II, and 3.0mm in group III. Ratio of tooth crown height to amount of alveolar bone resorption was 4.0:1 in groupI, 2.7:1 in group II, and 2.2:1 in group III, the ratio was decreased with age. 2. In comparison with upper teeth and lower teeth in ipsilateral side, the average value of tooth crown height and amount of alveolar bone resorption were slightly higher in upper arch than those in lower arch, but there was not a statistically significant difference. 3. The ratio of height of tooth crown to amount of alveolar bone resorption was decreased with age, and which depended mainly upon the change of amount of alveolar bone resorption rather than the change of tooth crown height.

• The Journal of the Korean dental association
• /
• v.56 no.6
• /
• pp.314-322
• /
• 2018

Among developmental anomalies of tooth shape, fusion and gemination are comparatively common. Developed with different etiologies, both fusion and gemination show similar clinical features. Therefore, many clinicians have difficulty diagnosing those morpho-anatomic anomalies. The purpose of this study is to report malformed right maxillary first molar in a 20-year-old female. With the aid of computed tomography (CT), the tooth was diagnosed as fusion with supernumerary tooth and dental caries lesion was detected. After performing direct pulp capping, the tooth was permanently restored with microhybrid composite resin using direct method to alter union groove into smooth surface for improving oral hygiene management. Until 6 months of follow-up visits, patient's chief complaint was resolved and tooth is still vital. In conclusion, identifying exact anatomy, conservative treatment and improving oral hygiene are essential in managing unusual morphologic anomalies of tooth.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.2
• /
• pp.246-251
• /
• 2010

Impactions can occur because of malpositioning of the tooth bud or obstruction in the path of eruption. However, the exact mechanism is still unknown. The impaction of mandibular first molar is rare with prevalence rates of 0.01~0.25%, but it is important to deimpact the tooth as soon as possible to avoid complications such as dental caries, root resorption, and periodontal problems on the adjacent teeth. Several biomechanical strategies have been proposed for uprighting mesially tipped mandibular first molars. However, most of these have had problems with movement of the anchorage unit because of the reciprocal force. The recent development of skeletal anchorage system(SAS) allows direct application of precise force systems to the target tooth or segment, producing efficient tooth movement in a short time. In this case, an impacted mandibular left first molar with dilacerated roots was treated with a miniplate, which provided skeletal anchorage to upright the tooth. The miniplate was installed in the mandibular ramus, and 10 months after the application of orthodontic force, the impacted tooth was exposed in the oral cavity and uprighted. At this point, the mandibular left first molar was included in the orthodontic appliance with fixed mechanotherapy, the tooth could achieve a normal occlusion. Therefore, the use of SAS simplified the orthodontic procedures and reduced the orthodontic treatment period, and had few side effects.

• The Journal of the Korean dental association
• /
• v.11 no.12
• /
• pp.787-799
• /
• 1973

Surveying the calcification degree of permanent tooth crown in 719 Korean children (Male 387, female 332) from 2 to 10 years old by orthopantomograph, the author got the following results. 1. Female was earlier than male in calcification of permanent teeth. 2. The results of the complete calcification of the permanent tooth crown were as follows. 3. The completion of calcification in the mandibular crown was seen earlier than that of the maxilla. 4. The order of calcification in permanent tooth crowns was as follows : 1 st molar, central incisor, lateral incisor, canine, 1st premolar, 2nd premolar, and 2nd molar. 5. The completion of calcification of the permanent crowns in Korean children was slightly retarded comparing with the Japanese and the American children.

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

• Journal of Korean Dental Science
• /
• v.5 no.1
• /
• pp.37-44
• /
• 2012

Purpose: Among the facilitation of tooth movement in adult orthodontic treatment methods, surgical approaches are gaining popularity but complications following mechanical bone reduction are a problem. In this study, tooth movement was observed after alveolar bone was chemically demineralized to verify whether tooth movement had been facilitated. Materials and Methods: Twelve rabbits were used. In the experimental group, the alveolar bone of the left first molar area was exposed and demineralized. Thirty seven percents phosphoric acid was applied for 5 minutes for demineralization. The opposite first molar area was used as control. Two teeth were pulled with 200 g force and 4 rabbits each were sacrificed at 3, 7, and 14 days after the force was applied. Histologic examination was done with hematoxylin and eosin and tartrate-resistant acid phosphatase staining. Result: The histologic examination results revealed more bone resorption in the demineralized area. As time passed, the number of osteoclasts increased in the compressed area. The amount of tooth movement was larger in the experimental group compared to the control group but the difference was not statistically significant. Conclusion: The demineralization with etchant resulted in limited bone resorption, more tooth movement and less damage of the cementum after applied orthodontic force.

• Journal of Periodontal and Implant Science
• /
• v.51 no.4
• /
• pp.285-295
• /
• 2021

Purpose: The aims of the present study were 1) to quantitatively evaluate the extent of sinus pneumatization and 2) to determine the factors affecting sinus pneumatization. Methods: Based on implant treatment records, a list of patients who underwent implant placement on the posterior maxilla was obtained. Among them, patients with pre-extraction and post-extraction (before implant placement) panoramic radiographs were selected. After excluding radiographs with low resolution and image distortion, the radiographs before and after extraction were superimposed using computer software. Subsequently, the extent of sinus pneumatization (the vertical change of the sinus floor) was measured. Simple and multiple mixed models were used to determine the factors affecting sinus pneumatization. Results: A total of 145 patients were eligible for the present investigation. The average extent of sinus pneumatization was 1.56±3.93 mm at 176 tooth sites. Male sex, single tooth extraction, extraction of an endodontically compromised tooth, a class I root-sinus relationship, and sinus membrane thickening >10 mm favored pneumatization, but without statistical significance. The maxillary second molar presented the greatest pneumatization (2.25±4.39 mm) compared with other tooth types. This finding was confirmed in the multiple mixed model, which demonstrated a statistically significant impact of the extraction of a second molar compared with the extraction of a first premolar. Conclusions: Maxillary sinus pneumatization was 1.56±3.93 mm on average. The extraction of a second molar led to the greatest extent of pneumatization, which should be considered in the treatment plan for this tooth site.

• The korean journal of orthodontics
• /
• v.45 no.4
• /
• pp.190-197
• /
• 2015

Objective: The aim of the study was to analyze the prevalence and distribution of ectopic eruption of the permanent maxillary first molar (EEM) in individuals scheduled for orthodontic treatment and to investigate the association of EEM with dental characteristics, maxillary skeletal features, crowding, and other dental anomalies. Methods: A total of 1,317 individuals were included and randomly divided into two groups. The first 265 subjects were included as controls, while the remaining 1,052 subjects included the sample from which the final experimental EEM group was derived. The mesiodistal (M-D) crown width of the deciduous maxillary second molar and permanent maxillary first molar, maxillary arch length (A-PML), maxillomandibular transverse skeletal relationships (anterior and posterior transverse interarch discrepancies, ATID and PTID), maxillary and mandibular tooth crowding, and the presence of dental anomalies were recorded for each subject, and the statistical significance of differences in these parameters between the EEM and control groups was determined using independent sample t -tests. Chi-square tests were used to compare the prevalence of other dental anomalies between the two groups. Results: The prevalence of maxillary EEM was 2.5%. The M-D crown widths, ATID and PTID, and tooth crowding were significantly greater, while A-PML was significantly smaller, in the EEM group than in the control group. Only two subjects showed an association between EEM and maxillary lateral incisor anomalies, which included agenesis in one and microdontia in the other. Conclusions: EEM may be a risk factor for maxillary arch constriction and severe tooth crowding.

• Journal of Korean society of Dental Hygiene
• /
• v.10 no.1
• /
• pp.81-92
• /
• 2010

Objectives : Thus this study attempted to look into the level of community residents' dental health and the state of their dental diseases and estimate the general dental health condition so that these data can be available as references in upcoming public dental health planning, and to provide fundamental data for promotion of the level of residents' dental health by performing dental health education. Methods : Among community residents who visited the department of Dental Hygiene of Shinsung University for scaling from March to May 2009, the data of total 346 subjects of 129 women and 217 men were selected, and DMFT rate, DMFT index, dental health capacity of the first permanent molar, and tooth morality rate were investigated. For statistical analysis, SPSS 14.0 was used, for general characteristics of the subjects, frequency analysis was conducted, for caries experience in the permanent teeth of the subjects, mean and standard deviation were calculated, for caries experience in the permanent teeth by sex and residence, independent t-test was performed, and for caries experience in the permanent teeth by age, one-way ANOVA was conducted. The significance level applied to these analyses was 0.05. Results : As a result of investigation and analysis on caries in the permanent teeth of community residents who visited the department for scaling in this study, the findings are as follows: 1. For sex, DMFT rate and tooth morality rate were found to be higher in women, while dental health capacity of the first permanent molar was found to be higher in men. 2. For age, DMFT rate and DMFT index were found to be highest in 40~49 years old, while DMFT rate, DMFT index, and tooth morality rate were found to be lowest in under 20 years old. Dental health capacity of the first permanent molar was found to be highest in under 20 years old, 20-29 years old, and 30-39 years old and found to be lowest in more than their sixties as 39.78 points(p<.000). Tooth morality rate was found to be highest in more than their sixties compared to other age groups.(p<.000). 3. For residence, DMFT rate and dental health capacity of the first permanent molar were found to be high in the Metropolitan area, while tooth morality rate was found to be high in Chungcheong area. Conclusions : Seen from the above-mentioned results, great importance shall be attached to the maintenance of residual teeth, and with this, efficient efforts are required to be made for upkeep and promotion of dental health.