• Journal of Periodontal and Implant Science
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• v.46 no.6
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• pp.415-425
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• 2016

Purpose: The present study investigated the impact of 2 different suture techniques, the conventional crossed mattress suture (X suture) and the novel hidden X suture, for alveolar ridge preservation (ARP) with an open healing approach. Methods: This study was a prospective randomized controlled clinical trial. Fourteen patients requiring extraction of the maxillary or mandibular posterior teeth were enrolled and allocated into 2 groups. After extraction, demineralized bovine bone matrix mixed with 10% collagen (DBBM-C) was grafted and the socket was covered by porcine collagen membrane in a double-layer fashion. No attempt to obtain primary closure was made. The hidden X suture and conventional X suture techniques were performed in the test and control groups, respectively. Cone-beam computed tomographic (CBCT) images were taken immediately after the graft procedure and before implant surgery 4 months later. Additionally, the change in the mucogingival junction (MGJ) position was measured and was compared after extraction, after suturing, and 4 months after the operation. Results: All sites healed without any complications. Clinical evaluations showed that the MGJ line shifted to the lingual side immediately after the application of the X suture by $1.56{\pm}0.90mm$ in the control group, while the application of the hidden X suture rather pushed the MGJ line slightly to the buccal side by $0.25{\pm}0.66mm$. It was demonstrated that the amount of keratinized tissue (KT) preserved on the buccal side was significantly greater in the hidden X suture group 4 months after the procedure (P<0.05). Radiographic analysis showed that the hidden X suture had a significant effect in preserving horizontal width and minimizing vertical reduction in comparison to X suture (P<0.05). Conclusions: Our study provided clinical and radiographic verification of the efficacy of the hidden X suture in preserving the width of KT and the dimensions of the alveolar ridge after ARP.

• Journal of TMJ Balancing Medicine
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• v.12 no.1
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• pp.1-6
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• 2022

Objectives: For the deviation phenomenon occurring during the treatment process in temporo-mandibular balancing medicine (TBM), hypotheses were established regarding the cause and mechanism of formation from the perspective of neuro-science and material mechanics, and a verification method was proposed. Methods: The deviation phenomenon was theoretically analyzed based on the structure theories of material mechanics of the joint and the neurological pain mechanism. Results: Deviation occurs due to temporary yield by the accumulation of heterogeneous stress in the temporo-mandibular joint and the affected joint. Because the joint structures are corresponding with material mechanics showing compressive and tensile properties. The size of the deviation is expressed in terms of strain. The occlusal surface of the teeth is level with the axial joint. Since the magnitude of the deviation has a proportional relationship with the degree of abnormality of the temporo-mandibular joint, the magnitude of the deviation calculated by the balance measurement can be replaced by the strain. The major variables involved in the occurrence of deviations are the strength of joint structures and neurological conditions. Therefore plastic deformation and adaptation occur as a long-term depression of neural circuits is strengthened in different ways at different locations each time in various clinical situations. This is the reason why the sequence of the restoration process while correcting deviations is following reverse order of the accumulation in many layers in the muscular nervous system. Conclusions: From the above results, it can be inferred that the occurrence and correction of the deviations are corresponding with the plastic deformation and neuro-plasticity.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.385-391
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• 2003

The purpose of this study is to examine the viability of PDL cells in rat molars by using MTT assay and to verify the MTT assay through the histologic observation. Thirty of Sprague-Dawley white female rats of 4-weeks old with a body weight of about 100 grams were used. Groupings are as follows : Immediate Group : Positive control group(n=10)-after extraction immediately. Dried Group : Negative control group(n=10)-after drying for an hour under warm dry. $ViaSpan^{\circledR}$ Group : 1hour $ViaSpan^{\circledR}$ group(n=10)-after storing in $ViaSpan^{\circledR}{\;}at{\;}4^{\circ}C$ for 1hour. Ten teeth of each group were treated as same as above and replanted to the original socket of experimental animals. After two weeks of replantation. all the experimental animals were sacrificed. And after fixation, extracted maxillary jaw was dimineralized. After it was embedded in paraffin. serial section by $5\mu\textrm{m}$ was carried out and for construction of specimen, hematoxylin-eosin dye was used. The mean MTT measurement of immediate group(positive control) is 2.81 and the mean measurement of dried group(negative control) is 0.98 which is significantt differnt(P<0.05), The mean measurement of $ViaSpan^{\circledR}$ group is 2.65 and there is significant difference between dried group and $ViaSpan^{\circledR}$ group(P<0.05), However, there is no difference between immediate group and $ViaSpan^{\circledR}$ group. The average resorption points of immediate group is 3.03 points. In the dried group, average 6.44 points resorption and 2.68 points showed resorption in the $ViaSpan^{\circledR}$ group. Unlike with MTT assay, there was no significant difference between the immediate group and $ViaSpan^{\circledR}$ group. The usage of MTT assay as a viable cell marker may give us a better indication of the maintenance of periodontal ligament cell vitality.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.35-45
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• 2009

This survey study was conducted on dental technician school students in April 2008 to investigate the effects of smoking on oral health. 110 male and 39 female students were surveyed and cross analysis was performed to examine the relationship between oral health status and smoking-related and oral health maintenance characteristics of smoking and non-smoking group. T-test and one-way ANAVA was used to analyze the average difference verification of two independent samples(smoking group and non-smoking group) and followings are the results. In general characteristics, 74 male students(74.7%) and 25 female(25.3%) students smoked and the percentage of male students were higher in smoking group. Regarding class grade, 2nd-year students(37 students, 37.4%) and 1st-year students(18 students, 36.0%) took the highest percentage of smoking and non-smoking group, respectively. Concerning the experience of drinking, smoking group consumed more alcoholic beverages(94 students, 94.9%) With respect to the frequency of between-meal consumption, respondents who eat between-meal once or twice smoked more. Respecting preferences of sweet food, respondents who enjoyed sweet food smoked more. Concerning smoking characteristics, many of smoking group had been smoked fo a long time(two to five years) and it was worrisome. About the amounts of smoking, 50 respondents(52.6%) of smoking group smoked 20 cigarettes a day with the highest proportion. With regard to the awareness of harmfulness, 70 respondents(70.7%) considered smoking as very harmful and showed that smoking group were aware of its harmfulness but it was habitualized. Respecting smokers in family members, father was more common as smokers(58 respondents, 58.6%) in family and showed that the influence of father. Main reasons of poor periodontal health were alchoholic consumption, smoking, and oral parafunctional habit(57 respondents, 56.7%) in smoking group and neglect of oral hygiene(21 respondents, 42.0%) in non-smoking group. With regard to the scaling, 80 respondents of smoking group(80.8%) didn't received scaling and showed that more oral health education was required. Regarding the periodontal status, non-smoking group was $1.26{\pm}0.44$, respondents who received scaling was $1.43{\pm}0.50$, respondents who regularly floss was $1.50{\pm}0.52$, respondents who brush more than three times a day was $1.38{\pm}0.49$ and had better periodontal health. Bleeding during tooth brushing was more frequent in smoking group ($1.51{\pm}0.70$). Regarding mouth order, non-smoking group was $2.34{\pm}0.62$, after scaling was $2.02{\pm}0.76$, patients who regularly floss was $1.50{\pm}0.52$, patients who brush more than three times a day was $1.81{\pm}0.87$. Concerning the experience of dental caries treatment, smoking group was $1.20{\pm}0.40$, patients who do not floss was $1.30{\pm}0.46$, patients who brush once a day was $1.29{\pm}0.45$. With regard to dental prosthesis, non-smoking group was $3.78{\pm}1.62$, patients who received scaling was $1.43{\pm}0.50$, patients who regularly floss was $1.40{\pm}0.51$, patients who brush more than three times a day was $1.24{\pm}0.43$. From these results, oral health education and smoking has correlation and more oral health education needs to be carried out to educate students with non-health related majors about harmfulness of smoking on oral health. Also more study are required.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.2
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• pp.72-80
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• 2019

Purpose: The purpose of this study is to compare and analyze the shear bond strength and fracture pattern in different enamel tooth surface treatments for resin splinting materials. Materials and Methods: G-FIX and LightFix were used as tooth splinting materials. Twenty bovine mandibular incisors were used for the preparation of the specimens. The exposed enamel surface was separated into four parts. Each tooth was treated with 37% phosphoric acid, 37% phosphoric acid + adhesive resin, 37% phosphoric acid + G-premio bond, and G-premio bond for each fraction. Shear bond strength was measured using a universal testing machine. After measuring the shear bond strength, the fractured surface of the specimen was magnified with a microscope to observe the fracture pattern. Two-way ANOVA was used to verify the interaction between the material and the surface treatment method. One-way ANOVA was used for comparison between the surface treatment methods of each material and post-hoc test was conducted with Scheffe's test. An independent t-test was conducted to compare shear bond strengths between materials in each surface treatment method. All statistics were conducted at 95% significance level. Results: G-FIX, a tooth splinting resin, showed similar shear bonding strength when additional adhesive resins were used when material was applied after only acid etching, and LightFix showed the highest shear bonding strength when additional adhesive resins were used after the acid etching. In addition, both G-FIX and LightFix showed the lowest shear bond strength when only self-etching adhesive was applied without additional acid etching. Verification of interactions observed interconnection between resins and surface treatment methods. Most of the mixed failure was observed in all counties. Conclusion: When using G-FIX and LightFix, which are tooth-splinting materials, it is considered that sufficient adhesion will be achieved even after applying only acid etching as instructed by the manufacturer.