• The korean journal of orthodontics
• /
• v.28 no.4 s.69
• /
• pp.533-546
• /
• 1998

A Skeletal Class III malocclusion may be the result of a large mandible, a small maxilla or combination of the two. Protraction devices for the maxilla are used to promote the growth of a deficient maxilla by applying extraoral force to actively growing patients. This study has been performed to determine whether there are significant differences in skeletal and dental changes between FH/Pal 1 and FH/Pal 2 group, SNA 1 and SNA 2 group, SNB 1 and SNB 2 group, and LFH 1 and LFH 2 group after RME and facial mask therapy. The results of this study can be summarized and concluded as follows ; 1. In all patients after maxillary protraction, the maxilla and maxillary dentitions moved forward, and the mandible rotated backward and downward. In most of them, palatal plane is tends to have an upward inclination. 2. The FH/Pal group 1, having an upward inclination of the palatal plane as a result of Facial mast showed statistically significant maxillary forward movement compared to the FH/Pal group 2. 3. The SNA group 1 showed significantly less mandibular backward movement and there was a tendency for the palatal plane to upward inclination compared to SNA group 2. 4. The SNB group 1 showed significantly less maxillary forward movement, but the vertical dimension, especially the lower facial height increased by mandibular downward rotation compared to SNB group 2. 5. LFH group 1, which had large saddle angle and posterior positioned mandible in the pre-treatment stage, showed maxillary protraction effect without significant increase in lower facial height compared to LFH group 2.

• The korean journal of orthodontics
• /
• v.39 no.6
• /
• pp.362-371
• /
• 2009

Objective: The purpose of this study was to compare the longitudinal treatment effects of facemask with rapid maxillary expansion (FM/RME) and chincup (CC) therapy followed by fixed orthodontic treatment (FOT) in Class III malocclusion (CIII) patients. Methods: The samples consisted of twenty-one CIII patients who had similar skeletal and dental characteristics before FM/RME or CC therapy and good retention results (Class I molar/canine relationship and positive overbite/overjet) after FOT (Group 1, FM/RME, n = 11; Group 2, CC, n = 10). Lateral cephalograms were taken before (T0) and after FM/RME or CC therapy (T1), and after FOT and retention (T2). Skeletal and dental variables were measured. Mann-Whitney U-test and Wilcoxon signed-rank test were used for statistical analysis. Results: During T0-T1, FM/RME therapy induced forward movement of point A, and labioversion of the upper incisors. Both groups showed posterior repositioning of the mandible. FM/RME resulted in increase of the vertical dimension; however, CC caused an increase in articular angle and decrease in gonial angle. During T1-T2, both groups exhibited forward growth of point A. Group 1 showed forward growth and counterclockwise rotation of the mandible and increase of IMPA; however, Group 2, showed increase of ANS-Me/N-Me and decrease of overbite. Conclusions: The key factor for successful FM/RME and CC therapy and good retention results might be a harmonized forward growth of the maxilla that could keep pace with the growth and rotation of the mandible.

• Journal of Periodontal and Implant Science
• /
• v.36 no.2
• /
• pp.555-565
• /
• 2006

The purpose of the present study is to evaluate the biological stability of the zirconia/alumina composite abutment by histologic and radiographic examination in clinical cases. 17 partially edentulous patients (5 men and 12 women, mean age 47) were treated with 37 implants. The implants were placed following the standard two-stage protocol. After a healing period of 3 to 6 months, zirconia/alumina composite abutments were connected. All radiographs were taken using paralleling technique with individually fabricated impression bite block, following insertion of the prosthesis and at the 3-, 6-, 12 month re-examinations. After processing the obtained images, the osseous level was calculated using the digital image in the mesial and distal aspect in each implant. An ANOVA and t-test were used to test for difference between the baseline and 3-, 6-, 12 months re-examinations, and for difference between maxilla and mandible. Differences at P <0.05 were considered statistically significant. For histologic examination, sample was obtained from the palatal gingiva which implant functioned for 12 months. Sections were examined under a light microscope under various magnifications. Clinically, no abutment fracture or crack as well as periimplantitis was observed during the period of study. The mean bone level reduction(${\pm}standard$ deviation) was 0.34 rom(${\pm}\;0.26$) at 3-months, 0.4 2mm(${\pm}\;0.30$) at 6-months, 0.62 mm(${\pm}\;0.28$) at 12-months respectively. No statistically significant difference was found between baseline and 3-, 6-, 12-months re-examinations (p > 0.05). The mean bone level reduction in maxilla was 0.33(${\pm}0.25$) at 3-months, 0.36(${\pm}0.33$) at 6-months, 0.56(${\pm}0.26$) at 12-months. And the mean bone level reduction in mandible was 0.35(${\pm}0.27$) at 3-months, 0,49(${\pm}0.27$) at 6-months, 0.68(${\pm}0.30$) at 12-months. No statistical difference in bone level reduction between implants placed in the maxilla and mandible. Histologically, the height of the junctional epithelium was about 2.09 mm. And the width was about 0.51 mm. Scattered fibroblasts and inflammatory cells, and dense collagen network with few vascular structures characterized the portion of connective tissue. The inflammatory cell infiltration was observed just beneath the apical end of junctional epithelium and the area of direct in contact with zirconia/alumina abutment. These results suggest the zirconia/alumina composite abutment can be used in variable intraoral condition, in posterior segment as well as anterior segment without adverse effects.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.34 no.4
• /
• pp.280-289
• /
• 2018

Purpose: The purpose of this randomized clinical trial is to determine whether implant length and the crown-to-implant (C/I) ratio influence implant stability and peri-implant marginal bone loss (MBL). Materials and Methods: 46 patients with single tooth missing in the posterior molar region of the mandible were included in this study. 19 implants (CMI IS-III $active^{(R)}$ long implant) of 5.0 mm diameter and 10 mm length were installed for the control group, while 27 implants (CMI IS-III $active^{(R)}$ short implant) of 5.5 mm diameter and 6.6, 7.3 or 8.5 mm length were placed for the experimental group. Each implant was inserted and immediately loaded using the digitally pre-fabricated surgical template and provisional restoration. The CAD-CAM monolithic zirconia crown was fabricated at 3 months after the surgery as a definitive restoration. The ISQ value and the MBL was measured at 48 weeks after the surgery. The correlation between the C/I ratio, MBL, and secondary implant stability was analyzed. Results: Successful results in terms of ISQ and MBL were achieved with both groups. There was no significant difference between the groups in terms of ISQ values and MBL at 48 weeks after the surgery (P > 0.05). No significant correlation was found between the C/I ratio and secondary stability as well as the C/I ratio and the MBL (P > 0.05). Conclusion: The influence of C/I ratio in both groups was not shown on the stability nor the marginal bone loss in implants supporting single crown of the mandible. Short implant could be a preferable alternative option in the reduced bone height mandible under the limited condition despite its higher C/I ratio.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.30 no.4
• /
• pp.278-288
• /
• 2014

Purpose: The aim of the study was to evaluate preprosthetic initial survival rate and factors associated with survival of osseointegrated implants placed in edentulous area of maxilla and mandible and to suspect the possible causes leading to failure. Materials and Methods: A total of 2158 endosseous implants that had been inserted between 2004 through 2013 were placed in 770 patients. The clinical comparisons were performed to evaluate implant loss in relation to age and gender of patients, position, system, length and diameter of implant, and bone graft technique. Results: According to position, the survival rates were 98.23% in maxillary anterior site, 96.98% in maxillary posterior site, 97.85% in mandibular anterior site and 98.76% in mandibular posterior site (P < 0.05). According to diameter of implant, the survival rates were 100% under 3.0 mm, 97.09% between 3.0 to 3.5 mm, 98.19% between 3.5 to 4.0 mm and 98.29% between 4.0 to 4.5 mm but relatively lower survival rate was 75% in 5.0 mm-over (P < 0.05). The survival rates of implants were 89.51%, 98.28%, 98.34% and 99.27% in the group with isolated sinus graft, with isolated GBR, with sinus graft and GBR simultaneously and without bone graft, especially (P < 0.05). Conclusion: This study establishes a relationship between survival rate of implant and position, diameter of implant system and bone graft technique. In conclusion, there were low survival rates in maxillary posterior site, in dental implants with wide diameter of 5 mm-over, and in the group with isolated sinus graft.

• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.2
• /
• pp.125-136
• /
• 2008

Statement of problem: Since the concept of osseointegration in dental implants was introduced by $Br{{\aa}}nemark$ et al, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. Purpose: The aim of this retrospective study was to provide long-term data on the $Neoplan^{(R)}$ implant, which features a sandblasted and acid-etched surface and external connection. Material and methods: 96 $Neoplan^{(R)}$ implants placed in 25 patients in Yonsei University Hospital were examined to determine the effect of the factors on marginal bone loss, through clinical and radiographic results during 18 to 57 month period. Results: 1. Out of a total of 96 implants placed in 25 patients, two fixtures were lost, resulting in 97.9% of cumulative survival rate. 2. Throughout the study period, the survival rates were 96.8% in the maxilla and 98.5% in the mandible. The survival rates were 97.6% in the posterior regions and 100% in the anterior regions. 3. The mean bone loss for the first year after prosthesis placement and the mean annual bone loss after the first year for men were significantly higher than that of women (P<0.05). 4. The group of partial edentulism with no posterior teeth distal to the implant prosthesis showed significantly more bone loss compared to the group of partial edentulism with presence of posterior teeth distal to the implant prosthesis in terms of mean bone loss for the first year and after the first year (P<0.05). 5. The mean annual bone loss after the first year was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. No significant difference in marginal bone loss was found in the following factors: jaws, type of prostheses, type of opposing dentition, and submerged /non-submerged implants (P<0.05). Conclusion: On the basis of these results, the factors influencing marginal bone loss were gender, type of edentulism, and location in the arch, while the factors such as arch, type of prostheses, type of opposing dentition, submerged / non- submerged implants had no significant effect on bone loss. In the present study, the cumulative survival rate of the $Neoplan^{(R)}$ implant with a sandblasted and acid-etched surface was 97.9% up to a maximum 57-month period. Further long-term investigations for this type of implant system and evaluation of other various domestic implant systems are needed in future studies.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.22 no.2
• /
• pp.185-193
• /
• 1992

The purpose of this study was to evaluate the prevalence and distribution of tooth number anomaly by means of the analysis of panoramic radiographs in 6,531 patients visited the Dental Infirmary of Kyungpook National University Hospital from January 1983 to May 1992. The results were as follows: 1. The prevalence of congenitally missing teeth except third molar was revealed to be 10.8%, and there was a hihger prevalence in females(44.6%) than in males(55.4%). Mandibular 2nd premolars(23.2 %) were absent most frequently, followed by maxillary lateral incisors(18.4 %), mandibular lateral incisors(18.3%), and maxillary second premolars(15.4 %) in descending order of frequency. As to the number of congenitally missing teeth, the percentage of missing one tooth was 48%, missing two teeth was 35.4 %, missing three teeth was 6.6%. 2. he prevalence of congenitally missing third molars was revealed to be 39.7%. There was a higher prevalence n the maxilla(60.3%) than in the mandible(39.7%). Maxillary right 3rd molars(30.6%) were absent most frequently, followed by maxillary left 3rd molar(29.7%), mandibular right 3rd molar(202%), mandibular left 3rd molar(19.5%) in descending order of frequency. 3. The prevalence of supernumerary teeth was revealed to be 4.2%, and there was a higher prevalence in males(65.7%) than in females(34.3 ). They were ound most frequently in maxillary central incisor area(64.8%), followed by maxillary lateral incisor area(132%), posterior area of maxillary third molar(8.7%) in descending order of frequency. As to the number of supernumerary teeth; The percentage of one supernumerary tooth was 79.9%, two supernumerary teeth was 8.9%, three supernumerary teeth was 1.2 %.

• Journal of Yeungnam Medical Science
• /
• v.14 no.1
• /
• pp.197-208
• /
• 1997

The purpose of this study was to evaluate the amount and interrelationship of the soft and hard tissue change after mandibular setback surgery in skeletal Class III malocclusion. The sample consisted of 25 adult patient (12 male and 13 female) who had severe anteropostrior skeletal discepancy. These patient had received presurgical orthodontic treatment and surgical treatment which is bilateral sagittal split ramus osteotomy. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC program. The result were as follows: 1. After mandibular bilateral sagittal split ramus osteotomy, lower facial soft. tissue horizontal posterior changes were high significance value. but vertical soft tissue changes were low significance value. 2. After mandibular bilateral sagittal split ramus osteotomy, relative upper lip protrusion increased(p<0.01) and relative lower lip protrusion decreased(p<0.01) and lower facial soft tissue thickness increased(p<0.01).

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.3
• /
• pp.229-236
• /
• 2009

Purpose: Some recent literatures report that it is possible to recover defected areas caused by enucleation of relatively large jaw cysts without using bone grafts. The aim was to find out whether spontaneous recovery of defected area with time occurred and what the contributing factors were. Materials and methods: In total, 194 patients were considered as patients. Out of these 194 patients, 74 patients who had no wound dehiscence and who were available for follow-up studies were selected. They were classified into two groups according to the size of radiolucent area in the preoperative panoramic radiographs: in one group, it was larger than $3{\times}4cm$, while in the other group, it was smaller than $3{\times}4cm$. Follow-up panoramic radiographs were taken immediately after the surgery, then after 3, 6, 9 and 12 months. On those radiographs, changes in size and density of the defected areas were observed using the Gray-level histogram of Adobe photoshop v7.0. Correlation between bone regeneration and factors such as the type and size of the cysts, age, sex, site of the cysts and systemic disease was evaluated using the General repeated measure and Mann-Whitney Test. Results: Analyses of panoramic radiographs showed that the recovery of radiopacity after 12 months was more than 97% on average in defected areas that were smaller than $3{\times}4cm$. in the defected areas that were larger than $3{\times}4cm$, considerable portion showed recovery of radiopacity. No statistically significant change was observed in bone density according to the type of cysts. Young patients under 20 years of age with highly active metabolism presented more significant bone regeneration than patients over 20 years of age. Bone regeneration was more hampered in patients who had medical disease, compared with patients who didn’t have any medical problem. No statistically significant change was seen in bone density according to sex. Changes in bone density according to the site of cysts such as maxilla, mandible, anterior or posterior region were not considered to be significant. Conclusion: Analyses of panoramic radiographs suggest that in approximately 12 months after the enucleation of cysts, clinically acceptable spontaneous bone regeneration can be observed even though normal bone graft procedures have not been applied.

• The korean journal of orthodontics
• /
• v.22 no.3 s.38
• /
• pp.491-507
• /
• 1992

Biennial serial cephalometric radiographs of 47 children (26 boys, 21 girls) were used to analyze the craniofacial growth changes in Korean children from 8 years to 16 years of age. A craniofacial model was designed for this study. It consisted of 72 anatomical points and 98 derived points. The craniofacial changes of these samples during these ages might be summarized as follows: 1. Mandibular growth to cranial base was more forward than maxillary growth. 2. Mandibular growth during this period was found to be a forward-upward (bite closing) rotation of the mandible. 3. Growth changes in total mandibular length (Ar-Gn) showed a pubertal growth spurt at 12-14 years of age in boys and 10-12 years of age in girls. Synchrony of the growth spurts on total mandibular length (Ar-Gn) and standing body height was found. 4. The pubertal spurts occured in the growth of total cranial base (Ba-Na) at 10-12 years of age in boys and 8-10 years of age in girls. The time of the spurts of the cranial base growth was 2 years ahead of that of the total mandibular growth. 5. Synchrony of growth spurts in anterior facial height (Na-Me), posterior facial height (S-Go) and body height was found. 6. The whole craniofacial changes during this period were plotted by using a X-Y plotter and personal computer. A simple profilogram for an diagnostic tool was obtained.