• The Journal of Korean Academy of Prosthodontics
• /
• v.52 no.1
• /
• pp.42-47
• /
• 2014

Decrease of occlusal vertical dimension (OVD) due to loss of teeth structure and destruction of the occlusal plane by severely worn dentition may cause cross bite or temporomandibular joint disorder by following change of facial feature or the loss of anterior guidance. Full mouth rehabilitation via an increase of the OVD can be considered to avoid this problem and proper evaluation of patient's OVD is essential. An 80 year old male visited for overall prosthodontic treatment, cross bite due to continuous wear and following decrease of the OVD were observed. We analyzed the existing occlusal relationship using the diagnostic cast, the radiographic evaluation and clinical test, and then proper increase of OVD was selected. The new OVD on diagnostic wax up was placed by the temporary restoration. After 3 months of observation period, final restoration with fixed partial dentures and implant overdenture were made. Throughout the follow-up period of 8 months, the aesthetic and functional improvement can be obtained.

• The korean journal of orthodontics
• /
• v.44 no.2
• /
• pp.88-95
• /
• 2014

Objective: The purpose of this study was to compare the treatment duration and dentoskeletal changes between two different anchorage systems used to treat maxillary dentoalveolar protrusion and to examine the effectiveness of en-masse retraction using two miniscrews placed in the midpalatal suture. Methods: Fifty-seven patients (9 men, 48 women), who had undergone level anchorage system treatment at Aichi-Gakuin University Dental Hospital (Nagoya, Japan) were divided into two groups according to the method of maxillary posterior anchorage reinforcement: midpalatal miniscrews (25 patients, mean age 22 years) and conventional anchorage (32 patients, mean age 19 years). The en-masse retraction period, overall treatment duration, pre-treatment effective ANB angle, and change in the effective ANB angle were compared with an independent-samples t -test. Results: Compared to the headgear group, the duration of en-masse retraction was longer by approximately 4 months in the miniscrew group (p < 0.001). However, we found no significant difference in the total treatment duration between the groups. Moreover, a greater change in the effective ANB angle was observed in patients treated with miniscrews than in those treated with the conventional method (p < 0.05). Conclusions: The level anchorage system treatment using miniscrews placed in the midpalatal area will allow orthodontists more time to control the anterior teeth during en-masse retraction, without increasing the total treatment duration. Furthermore, it achieves better dentoskeletal control than does the conventional anchorage method, thereby improving the quality of the treatment results.

• The korean journal of orthodontics
• /
• v.50 no.4
• /
• pp.268-277
• /
• 2020

This case report demonstrates two different uprighting mechanics separately applied to mesially tipped mandibular first and second molars. The biomechanical considerations for application of these mechanisms are also discussed. For repositioning of the first molar, which was severely tipped and deeply impacted, a novel cantilever mechanics was used. The molar tube was bonded in the buccolingual direction to facilitate insertion of a cantilever from the buccal side. By twisting the distal end of the cantilever, sufficient uprighting moment was generated. The mesial end of the cantilever was hooked over the miniscrew placed between the canine and first premolar, which could prevent exertion of an intrusive force to the anterior portion of the dentition as a side effect. For repositioning of the second molar, an uprighting mechanics using a compression force with two step bends incorporated into a nickel-titanium archwire was employed. This generated an uprighting moment as well as a distal force acting on the tipped second molar to regain the lost space for the first molar and bring it into its normal position. This epoch-making uprighting mechanics could also minimize the extrusion of the molar, thereby preventing occlusal interference by increasing interocclusal clearance between the inferiorly placed two step bends and the antagonist tooth. Consequently, the two step bends could help prevent occlusal interference. After 2 years and 11 months of active treatment, a desirable Class I occlusion was successfully achieved without permanent tooth extraction.

• Imaging Science in Dentistry
• /
• v.50 no.3
• /
• pp.217-226
• /
• 2020

Purpose: The purpose of this study was to analyze the quantity and quality of the mandibular anterior alveolar bone in terms of alveolar width, density, and total alveolar height (TAH) based on dental status, gender, and age. Additionally, this study aimed to quantitatively evaluate the available alveolar height for graft harvesting (AHGH) and examine its variability based on the aforementioned factors. Materials and Methods: This retrospective cone-beam computed tomographic study included a total of 100 subjects. On the basis of gender, dental status, and age, the scans were divided into 3 primary groups and 8 subgroups. The mandibular alveolar width and density were measured 5 mm mesial to the mental foramen bilaterally and at the midline. The TAH was measured at the midline, and the AHGH was measured as the midline distance between 5 mm apical to the root of the canines and 5 mm superior to the lower border. Results: The mandibular alveolar width was statistically similar between dentulous and edentulous patients (P>0.05). A significantly greater density was observed at the midline in edentulous patients (P<0.05). The TAH was significantly greater in edentulous male patients than in edentulous female patients (P<0.05). Dentulous and male patients had significantly greater AHGH than edentulous and female patients, respectively (P<0.05). Conclusion: Based on the data evaluated in this study, it can be concluded that the mandibular symphyseal area has adequate bone quality and quantity for bone graft harvesting for dental implant therapy.

• Journal of Periodontal and Implant Science
• /
• v.28 no.1
• /
• pp.177-185
• /
• 1998

Periodontal disease and/or loss of teeth brings pathologic tooth migration that can result in esthetic and occlusal problems. Diastema and general spacing of the teeth, particularly in the anterior segments of the dentition are frequently developed in individuals with advanced periodontal disease. Thus, the overall treatment plan for a patent with advanced periodontal disease often involves periodontal orthodontic combined therapy. Orthodontic treatment in adults with periodontal disease is restricted to tooth alignment with special caution. Indirect bonding can achieve accurate bracket placement. A 38 year old woman with adult periodontitis was treated by periodontal therapy. Subsequently, her diastema was orthodontically corrected by indirect bonding technique. It must be an appropriate case report of periodontal-orthodontic combined therapy.

• Journal of Biomedical Engineering Research
• /
• v.17 no.1
• /
• pp.61-70
• /
• 1996

In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony inyowth and secondary long term fixation. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone stem interface. An accurate evaluation of interf'ace micromotion and stress/strain fields in the bone-implant system may be relevant for better understanding of clinical situations and improving THA design. Recently finite element method(FEM) was introduced in'orthopaedic research field due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional finite element model of proximal femur with $Multilock^{TM}$ stem of 1179 blick elements to analyse the micromotions and mechanical behaviors at the bone-stem inteface in early post-operative period for the load simulating single leg stance. The results indicates that the values of relative motion for this well fit stem were $150{\mu}m$ in maximum $82{\mu}m$ in minimum and the largest relative motion was developed in medial region of Proximal femur and in anterior-posterior direction. The motion in the proximal bone was much greater than in the distal bone and the stress pattern showed high stress concentration on the cortex near the tip of the stem. These findings indicate that the loading on the hip joint in the early postoperative situation before achieving bony ingrowth could produce large micromotion of $150{\mu}m$ and clinicaly non-cemented THA patient should not be allowed weight bearing strictly early in the postoperative period.

• Journal of Periodontal and Implant Science
• /
• v.38 no.1
• /
• pp.15-22
• /
• 2008

Purpose: The attachment level is strongly associated with tooth loss and provides useful information on patterns of destruction of the periodontium. The presence of horizontal attachment loss would not be detected in clinical measurement. Therefore, the purpose of the present study was to estimate the patterns of periodontal destruction based on the attachment area and horizontal attachment loss in extracted teeth due to severe periodontitis. Materials and Methods: 307 teeth satisfied the criteria for assessment. An indirect method, based on digital images obtained from a digital camera and an image analysis program, was used to calculate the area of root surface and attachment loss and the extent of horizontal attachment loss. The data were analysed using SPSS. Results: No statistically significant differences among root surfaces were observed in anterior teeth on the loss of attachment area. However, in posterior teeth statistically significant differences in palatal surfaces of maxillary and mandibular premolar and molar surfaces compared with buccal surfaces were observed. Horizontal attachment loss was observed in 21.5% of the teeth examined. Frequency of horizontal attachment loss was highest in the maxillary first premolar (34.8%), followed by the maxillary second premolar (27.3%) and maxillary canine (25%). The mean length of horizontal attachment loss was 1.5mm. Conclusion: More meticulous examination will be needed of the palatal surfaces of maxillary and mandibular premolar and molar teeth. The percentage of teeth with horizontal attachment loss greater than 2.1 mm was 5.2%. Considering the length of curette blades, about 5.2% of teeth were not properly debrided. Therefore, Additional supportive therapy such as local drug delivery has to be considered in treatment of the first maxillary, second premolar and canine due to the high prevalence of horizontal attachment loss.

• Journal of Periodontal and Implant Science
• /
• v.50 no.4
• /
• pp.226-237
• /
• 2020

Purpose: This study was conducted to assess the efficacy of prophylactic gingival grafting in the mandibular anterior labial area for preventing orthodontically induced gingival recession. Methods: Eight mongrel dogs received gingival graft surgery at the first (I1) and third (I3) mandibular incisors on both sides based on the following group allocation: AT group (autogenous connective tissue graft on I1), AT-control group (contralateral side in the AT group), CM group (xenogeneic cross-linked collagen matrix graft on I3) and CM-control group (contralateral side in the CM group). At 4 weeks after surgery, 6 incisors were splinted and proclined for 4 weeks, followed by 16 weeks of retention. At 24 weeks after surgery, casts were made and compared with those made before surgery, and radiographic and histomorphometric analyses were performed. Results: Despite the proclination of the incisal tip (by approximately 3 mm), labial gingival recession did not occur. The labial gingiva was thicker in the AT group (1.85±0.50 mm vs. 1.76±0.45 mm, P>0.05) and CM group (1.90±0.33 mm vs. 1.79±0.20 mm, P>0.05) than in their respective control groups. Conclusions: The level of the labial gingival margin did not change following labial proclination of incisors in dogs. Both the AT and CM groups showed enhanced gingival thickness.

• Archives of Craniofacial Surgery
• /
• v.13 no.1
• /
• pp.22-28
• /
• 2012

Purpose: In accordance to an increased interest in facial appearance and the popularization of computed tomography scanning, the number of diagnosis and treatment of blowout fractures has been increased. The purpose of this article is to review pure blowout fracture surgery through transconjunctival incision focusing on complications and their management. Methods: In this retrospective study, 583 patients, who had been treated for pure blowout fracture through transconjunctival incision from 2000 to 2009, were evaluated. Their hospital records were reviewed according to their sex, age, fracture site, preoperative presentations, time interval between trauma and surgery, and postoperative complications. Results: According to postoperative follow-up results, there were early complications that included wound dehiscence and infection (0.2%), hematoma (insomuch as extraocular movement is limited) (0.7%), lacriminal duct injury (0.5%), and periorbital nerve injury (0.7%). In addition, there were late complications that lasted more than 6 months, that included persistent diplopia (1.7%), extraocular movement limitation (0.9%), enophthalmos (1.0%), periorbital sensation abnormalities (1.0%), and entropion (0.5%). Conclusion: We propose the following guidelines for prevention of postoperative complications: layer by layer closure; bleeding control with the epinephrine gauzes, Tachocomb, and Tisseel; conjunctival incision 2 to 3 mm away from punctum; avoidance of excessive traction; performing surgical decompression and high dose corticosteroid therapy upon confirmation of nerve injury; atraumatic dissection and insertion of Medpor Barrier implant after securing a clear view of posterior ledge; using Medpor block stacking technique and BioSorb FX screw fixation; performing a complete resection of the anterior ethmoidal nerve during medial wall dissection; and making an incision 2 to 3 mm below the tarsal plate.

• Journal of Periodontal and Implant Science
• /
• v.27 no.3
• /
• pp.585-595
• /
• 1997

Removal of subgingival calculus is essential for the success in periodontal treatment. Subgingival instrumentation is used for the removal of all bacterial plaque and calculus. In this study, two types of anterior curet were used on ant. teeth to conduct subgingival scaling and root planing. The remaining amount of calculus was evaluated according to type of instrument, depth of pocket, and tooth surface. 24 teeth extracted from patients being treated at Dan Kook University dept. Perio. were used. 4 surfaces per tooth a total of 96 areas were evaluated. 12 teeth treated with Gracey No. 1-2 was used as the control group and 12 teeth treated with Mini-five curet No. 1-2 was the experimental group. The 4 surfaces of the teeth {buccal, mesial, lingual or palatal, distal) were observed under a stereomicroscope and the images were captured 3 times per surfaced with a CCD. The image were observed on the monitor using a $10{\times]10$ grid produced with the Microsoft power point. The amount of calculus remaining was evaluated 3 times per surface. The results were as follows. 1. There was no significant difference in remaining calculus according to the pre-treatment pocket depth, and tooth position{Mx. or Mn). 2. The Mini-five curet showed better results than the Gracey curet but there was no statistically significant difference. 3. In both Gracey curet group and Mini-five curet group the lingual(or palatal) surface showed significant difference compared to the other surfaces(p<0.05). From the results above, it is thought that when treating ant. teeth consideration of the tooth surface is more important than the choice of instrument.