• Title/Summary/Keyword: Proximal contact strength

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Evaluation of proximal contact strength by postural changes

  • Kim, Hee-Sun;Na, Hyun-Joon;Kim, Hee-Jung;Kang, Dong-Wan;Oh, Sang-Ho
    • The Journal of Advanced Prosthodontics
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    • v.1 no.3
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    • pp.118-123
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    • 2009
  • STATEMENT OF PROBLEM. Proper proximal contact is important for maintaining and stabilizing the dental arch. However, the proximal contact strength (PCS) is not a constant value and can be affected by a variety of factors. PURPOSE. This study examined the influences of postural changes on the posterior PCS. MATERIAL AND METHODS. Twelve adults with a normal occlusion and had not undergone prosthetic treatment or proximal restoration were participated in this study. A metal strip was inserted into the proximal surface and removed at a constant velocity. The contact strength was measured in every contact point between canine to second molar in both arches. The PCSs were obtained initially in the upright position, secondly in the supine position and finally in the upright position again. All measurements were repeated after a 2 hour period. Statistical analysis was carried out using the Friedman test (P < .05). RESULTS. Generally, a decrease in PCS occurred when the posture was changed from the initial upright to supine position, while it increased when the posture was changed from the supine to upright position. A significant change was observed in all areas except for between the canine-first premolar in the maxilla and between the first molar-second molar in the mandible areas. CONCLUSION. The posterior PCS, which dentists generally believe to be a static feature of occlusion, is affected significantly by posture.

Food impaction related with trauma from occlusion (임플란트 보철물의 식편압입: 교합적 원인분석과 대처)

  • Cho, Lee-Ra
    • The Journal of the Korean dental association
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    • v.52 no.8
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    • pp.491-505
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    • 2014
  • Food impaction between the implant prostheses and adjacent teeth is the most frequently observed problem. It may be caused by the migration of the adjacent teeth. This symptom may be observed at the mesial aspect of implant prostheses especially, and related with the multiple contributing factors including teeth vitality and antagonist. Idal proximal contact with optimal strength and shape should be made for preventing the food impaction. Shape of customized abutment and prosthesis should have optimal emergence profile. Long duration from the extraction to the delivery of implant prostheses, the adjacent teeth and antagonist teeth may have possibility of occlusal interferences. Remained teeth mobility can induce the food impaction regardless of interproximal contact strength. Occlusal adjustment to remove occlusal interferences can be a method for enhancing the stability of interproximal contact.

The Effects of Taping, AMCT, Combination Treatment on the Pain and Grip Strength in Patient with Lateral Epicondylitis (테이핑, AMCT, 복합치료가 외측상과염 환자의 통증과 악력에 미치는 효과)

  • Kim, Eun-Young;Ma, Sang-Yeol;Gong, Won-Tae
    • Journal of the Korean Society of Physical Medicine
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    • v.3 no.2
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    • pp.103-112
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    • 2008
  • Purpose : The Purpose of this study was to investigate the effects of taping and AMCT(activator methods chiropractic technique) on the pain and grip strength in patients with lateral epicondylitis. Methods : To study divided of three groups. Taping groups were apply to taping was attached from wrist joint to elbow joint lateral epicondly after maximun flexion. AMCT application was contact the posterior aspect of the proximal head of the radius. The line of drive is anterior and inferior. Next, contact the anterior aspect of the lunate by positioning the instrument on the volar aspect of the wrist. The line of drive is straight posterior. combination groups was treated using the taping and AMCT application. Result : 1. The pain was decreased on taping groups, AMCT groups and combination groups of all(p<.05). 2. Power grip was enhanced in taping groups, AMCT and combination groups(p<.05). but taping, AMCT, combination groups was no difference compared with after 1 week therapy(p>.05). 3. Compared with AMCT and taping therapy about pain decreased was AMCT groups better than taping groups(p<.05). 4. Compared with AMCT and taping therapy about power grip was AMCT groups better than taping groups(p<.05). 5. AMCT and combination groups was no difference compared with pain release and power grip after therapy(p>.05). Conclusion : AMCT groups therapy are more effect able than taping therapy for grip strength and pain reduction. Hence, AMCT groups therapy is most effect able for pain reduction with lateral epicondylitis patients.

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ELASTIC CONSTANTS, SHEAR BOND STRENGTH OF TUNNEL RESTORATIVE MATERIALS AND MARGINAL RIDGE STRENGTH OF RESTORED TEETH (터널형 2급와동 충전재의 탄성계수와 전단결합강도 및 수복치의 변연융선 파절강도에 관한 연구)

  • Lee, Ka-Yean;Park, Yeong-Joon;Yang, Kyu-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.23 no.3
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    • pp.746-763
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    • 1996
  • An alternative design to conventional class II cavity preparation for proximal carious lesions is the tunnel preparation. It preserves the marginal ridge intact, thus making it possible to maintain the natural contact relationship with the adjacent tooth and minimize tooth reduction. This in vitro study was purposed to evaluate the effect of the materials' elastic constants and shear-bond strength on the marginal ridge fracture resistance of teeth restored by the tunnel technique, and to find the materials of choice for tunnel restorations. $Resinomer^{(R)}$, $Ketac-silver^{(R)}$, $Miracle-Mix^{(R)}$, and Tytin were used as restorative material. The elastic constants of each restorative material were evaluated by ultrasonic pulse measurement. Young's modulus and bulk modulus of the restorative materials were evaluated in three specimens for each material type. The shear-bond strength of the restorative materials to the dentin surface was measured after thermocycling 400 times between 6 and $60^{\circ}C$, using ten specimens for each material type. For measuring marginal ridge strength, 60 sound extracted molar teeth were distributed into six groups by size. Sound molar teeth were used as a Control group and unfilled prepared teeth were grouped as Unrestored. Another four groups were named Resinomer group, Ketac-Silver group, Miracle Mix group, and Tytin group by type of restorative material. Tunnel cavity preparation was done with ' 1/2, 2, and 4 round burs in sequence. Initial access to proximal surface was made through an occlusal access preparation started at least 2mm from the marginal ridge, and the proximal opening was formed about 2.5mm below the marginal ridge. After restoration and thermocycling, marginal ridge strength was measured using a universal testing machine. The results were as follows: 1. The Young's modulus of $Tytin^{(R)}$ was 63.95 GPa, followed by $Ketac-Silver^{(R)}$ 27.60 GPa, $Miracle-mix^{(R)}$ 18.48 GPa, and $Resinomer^{(R)}$ 10.74 GPa showing significant differences between the groups(P<0.05). The bulk modulus of the materials showed the same order as Young's modulus. The value of $Tytin^{(R)}$ showed 59.57 GPa indicating that it will deform less than other materials under the same stress. It was followed by $Ketac-Silver^{(R)}$ 23.57 GPa, Miracle $Mix^{(R)}$ 12.50 GPa, and $Resinomer^{(R)}$ 11.60 GPa. 2. The Resinomer group had a shear-bond strength of 7.41 MPa which was significantly higher than those of the Ketac-Silver group (1.80 MPa) and the Miracle Mix group (2.84 MPa) (P<0.01). All the specimens of Tytin group detatched from the dentin surface during thermocycling. 3. The mean marginal ridge strength of the Unrestored group(46.14 kgf) was significantly lower than that of the Control group (84.24 kgf) (P<0.01). The marginal ridge strength of teeth restored by the tunnel technique was, in order, Ketac-Silver group 74.06 kgf, Miracle Mix group 73.36 kgf, Resinomer group 63.47 kgf, and Tytin group 58.76 kgf. The Ketac-Silver, Miracle Mix, and Resinomer groups showed no significant difference with the Control group (P>0.05), but the Tytin group showed significantly lower strength compared to the Control group(P<0.05). The results showed that the marginal ridge strength of the teeth restored by the tunnel technique was not significantly lower than that of sound teeth. They also demonstrated that the bonding strength of the restorative material to the tooth surface should be high and the modulus of elasticity should not be lower than that of the tooth in order to restore the marginal ridge strength to its natural condition.

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The effect of increasing the contact surface on tendon healing

  • Bilgen, Fatma;Duman, Yakup;Bulut, Omer;Bekerecioglu, Mehmet
    • Archives of Plastic Surgery
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    • v.45 no.4
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    • pp.357-362
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    • 2018
  • Background The most common complication after tendon repair is the development of adhesion, with subsequent rupture. Methods In this study, we present a new method in which the tendon healing contact surface is increased to reduce these complications. The tendons of chickens in groups 1, 3, and 5 were transversely cut and repaired with in the traditional fashion with double-modified Kessler method and 5/0 polypropylene. In the other groups, 3 mm of the tendon was removed from the proximal half of the upper end and from the distal half of the lower end of the tendon, and they were repaired with the modified Kessler method. The tendons of the chickens in groups 1 and 2 were evaluated immediatelly after surgery. Groups 3 and 4 were evaluated at 4 weeks after surgery. Groups 5 and 6 were evaluated at 6 weeks. Results Increases in transient inflammation and connective tissue formation were observed more clearly in the group treated with the new method in histopathological investigations at weeks 4 and 6. The stretching test showed statistically significant differences between groups 3 and 4 (P<0.05) and groups 5 and 6 (P<0.05). Conclusions When repairing tendons with the new method, the healing surface increases and the direction of collagen fibers at the surface changes. Because of these effects, the strength of the tendon healing line increases; we therefore expect that this technique will enable patients to safely engage in early active exercise after the operation, with less risk of tendon rupture.