• The Journal of Advanced Prosthodontics
• /
• 제8권4호
• /
• pp.251-258
• /
• 2016

PURPOSE. This study was undertaken to investigate whether use of an adhesive penetration enhancer, dimethyl sulfoxide (DMSO), improves bond stability of fiber posts to root dentin using two two-step etch-and-rinse resin cements. MATERIALS AND METHODS. Forty human maxillary central incisor roots were randomly divided into 4 groups after endodontic treatment and post space preparation, based on the fiber post/cement used with and without DMSO pretreatment. Acid-etched root dentin was treated with 5% DMSO aqueous solution for 60 seconds or with distilled water (control) prior to the application of Excite DSC/Variolink II or One-Step Plus/Duolink for post cementation. After micro-slicing the bonded root dentin, push-out bond strength (P-OBS) test was performed immediately or after 1-year of water storage in each group. Data were analyzed using three-way ANOVA and Student's t-test (${\alpha}$=.05). RESULTS. A significant effect of time, DMSO treatment, and treatment${\times}$time interaction were observed (P<.001). DMSO did not affect immediate bonding of the two cements. Aging significantly reduced P-OBS in control groups (P<.001), while in DMSO-treated groups, no difference in P-OBS was observed after aging (P>.05). CONCLUSION. DMSO-wet bonding might be a beneficial method in preserving the stability of resin-dentin bond strength over time when fiber post is cemented with the tested etch-and-rinse adhesive cements.

• The Journal of Advanced Prosthodontics
• /
• 제6권3호
• /
• pp.215-223
• /
• 2014

PURPOSE. This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. MATERIALS AND METHODS. Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (${\alpha}$=0.05). The alloy toxicity was evaluated according to the ISO standard. RESULTS. The solidus and liquidus points of experimental alloys ranged from $1023^{\circ}C$ to $1113^{\circ}C$ and increased as the nickel content increased. The highest ultimate tensile strength ($595.9{\pm}14.2$ MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity ($113.9{\pm}8.0$ and $122.8{\pm}11.3$ GPa, respectively), but also had a value of 0.2% proof strength ($190.8{\pm}4.8$ and $198.2{\pm}3.4$ MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. CONCLUSION. The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.

• Restorative Dentistry and Endodontics
• /
• 제10권1호
• /
• pp.31-42
• /
• 1984

The toxic effect of adhesive resins on the dog's pulp tissue was studied with 70 teeth from 5 dogs. The experimental materials were Clearfil, a mixture of Clearfil with calcium hydroxide powder, Panavia-EX, and a mixture of Panavia-EX with calcium hydroxide powder. As a control group, calcium hydroxide powder was used. Each material was placed on the pulpotomized tissue surface. After 3 days, 1, 2,4, and 6 weeks, the teeth and apical tissue were processed routinly and stained with hematoxylin and eosin. Pathological tissue changes due to the toxicity of adhesive resins were observed by light microscope, and the pH of Panavia-EX and the Bonding agent of Clearfil were measured. Following were the results; 1. In the group of calcium hydroxide powder, slight inflammatory change was observed in the pulpotomized surface and adjacent pulp tissue on 3 day. 1 week case showed incomplete dentin bridge. The remaining pulp tissue was normalized according to the days elapsed. 2. In the group of Clearfil, early inflammatory change revealed in the superificial portion of the remaining pulp tissue on 3 day. The inflammation spreaded over the total pulp tissue and partial necrosis was observed in 1 week and 2 week cases. Total necrosis of pulp tissue and moderate inflammatory change at the apical tissue was noticed in 4 week and 6 week cases. 3. In the group of Panavia-EX, moderate inflammatory change appeared in the superficial pulp tissue on 3 day, and severe inflammatory change over all pulp tissue found in 1 week case. Pulp necrosis was obvious in 2 week case. 4 week and 6 week cases were totally necrotized up to the periapical tissue. 4. In the groups of mixtures with calcium hydroxide powder, the pulp tissue destruction was retarded, compared with the groups of Clearfil and Panavia-EX. 5. Panavia-EX was more destructive than Clearfil. 6. The acidity of freshly mixed Bonding agent of Cleafil was pH 4.0, and that of Panavia-EX was pH 2.0.

• Restorative Dentistry and Endodontics
• /
• 제1권1호
• /
• pp.26-32
• /
• 1975

After a vital pulpotomy in dogs' teeth, the responses of the remaining pulp tissue under hydroxides (calcium hydroxide, magnesium hydroxide, aluminium hydroxide and zinc hydroxide) were studied histologically. The class V cavities were prepared on the teeth and the pulp was amputated. Each hydroxide was placed over the amputated tissue and the cavity was sealed with zinc oxide eugenol cement. Animals were sacrificed after 3 days, 1, 2, and 3 weeks following the operation. The teeth were decalcified, sectioned and stained with hematoxylin and eosin. Microscopic examination reveals as follows; 1. Calcium hydroxide: Inflammatory change was seen in the superficial portion of the remaining pulp tissue at the 3rd day and 1st week. The incompleted calicified material began to be deposited from the canal wall at the 2nd week, and the advanced calcified material was seen at the 3rd week. 2. Magnesium hydroxide: Severe inflammatory change was seen in the superficial portion of the remaining pulp from the 3rd day and the 1st week samples. Inflammatory change was decreased at the 2nd week and the slight calcified material was deposited from the root canal at the 3rd week. 3. Aluminium hydroxide: Severe inflammatory changes were seen in the remaining pulp tissue, the blood vessel was dilated, and the odontoblasts were destroyed at the 3rd day and 1st week. The fibrous degeneration spread to the apex at the 2nd week. There was no evidence of newly formed odontoblasts or deposition of calcified material underneath aluminium hydroxide. 4. Zinc hydroxide: The micrscopic picture was destructive. A thick necrotic layer was found under the amputated surface at the 3rd day and 1st week. Granulation tissue formation as well as chronic inflammatory changes extended to the apical area in the pulp tissue. Also there were no sign of odontoblastic formation or calcified material at the 2nd and 3rd week.

• Restorative Dentistry and Endodontics
• /
• 제12권1호
• /
• pp.155-163
• /
• 1986

The purpose of this study was to measure penetration of dye stuff (2% Methylene blue, 2% Hematoxylin, 2% crystal violet and 2% safranin-O) on unfilled resin (Lang Dental MFG Co.) Hipol (Boopyung Dental Chemical Co. Macrocomposite resin) Durafill (Kulzer, Co. Microfilled Composite resin) and Heliosit (Vivadent Co. Microfilled Composite resin) The unfilled resin with dough stage was inserted into plastic tuble (5mm in diameter and 4mm in height) with condensation force of 1000 gr, 2000 gr and without condensation force. Hipol mixed on the mixed pad was inserted into the plastic tube by the same method as the unfilled resin. The microfilled resins which were Durafill and Heliosit were polymerized for 60 seconds with the visible light on each surface of the plastic tube which was upper and lower, under condensation force of 1000 gr, 2000 gr and without condensation force. All specimens were stored in the air for 24 hours, then specimens were immersed in the various kind of dye solution for different period of time (1 hour and 24 hours). These dye-treated specimens were polished horizontally until removing 0.5mm of each surface on the emery paper (#1000), and the dye penetration in the polished surface was measured under the digital microscope (Japan Fosuh). Following results were obtained 1. The penetration of dyes was the most excessive in Durafill and was not influenced on the condensation force and the period of immersion time. 2. All dyes were penetrated into Hipol, and Crystal violet was penetrated most excessively in all dyes. 3. The penetration of dye in all resins was not influenced by the period of immersion time and condensation force. 4. There was no evidence of dye penetration in unfilled resin.

• Restorative Dentistry and Endodontics
• /
• 제3권1호
• /
• pp.17-21
• /
• 1977

After a vital pulpotomy in dogs' teeth, the responses of the remaining pulp tissue under calcium hydroxide and formocresol were studied histologically. The class I and V cavities were prepared on the teeth and the pulp was amputated. Calcium hydroxide and formocresol were placed over the amputated tissue and the cavities were sealed with zine oxide eugenol cement and zinc phosphate cement. Animals. were sacrifice after 1, 2, and 3 weeks following the operation. The teeth were decalcfied, sectioned and stained with hematoxylin and eosin. Microscopic examination reveals as follows; 1. Healing of the pulp at the amputation site did not occur in the pulps treated with formocresol. 2. At one week, a thin layer of darker staining tissues just below the necrotic zone was presented in the pulps treated with formocresol. In this stage the tissues beneath the darker staining layer were normal. 3. At two weeks, the cells of the palest staining layer were showed indistinct nucleus which suggested the karyolysis and the karyorrhexis in the pulps treated with formocoresol. As reached to the middle third of the pulp, the odontoblasts were scarcely evident or missed in this stage. 4. At three weeks, the necrotic zone was reached to the middle third of the pulp canal. The cells beneath the zone showed massive infiltration of inflammatory cells in the pulps treated with formocresol. 5. Dentin bridge in the control group was deposited below the necrotic zone from the two. weeks later. 6. Normal tissues were observed ill the apical third of all. the dental pulps in all case of calcium hydroxide and formocresol.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제30권4호
• /
• pp.359-369
• /
• 2008

Purpose: Fractures of the mandibular condyle accounts for 15% to 30% of all the mandibular fractures and lots of complications are reported. Among these complications, condylar resorption is the most important one to be taken into account. The purpose of this study is evaluating condylar resorption pattern in relation to extracorporeal fixation technique. Patients & methods: Thirty four patients with 42 mandibular condylar fractures were retrospectively examined with an average follow-up of 18.5 months (6-66 months). Male/female ratio is 27 males (7 bilateral cases) and 7 females (1 bilateral case). Applicated surgical techniques were extracorporeal fixation via submandibular approach and extracorporeal fixation via intraoral approach. We compared radiographic views of post-operative periods with that of most long term follow up in 34 operated sites respectively. Result: There were 2 generalized condylar resorption sites and 3 partial resorption sites with clinical implications. Others (29 joints) showed good healing or satisfactory adaptive state of temporomandibular joints clinically. Radiologically, signs of partial condylar resorption and/or osteoarthrosis were diagnosed in 11 patients. But, 8 out of the 11 patients didn't show significant clinical symptoms, which means successful adaptive remodeling of the surgically located condylar head. Conclusion: From the above results, intentional ramal osteotomy, temporary detachment of the fractured condyle and extracorporeal fixation technique seems to be effective and useful in those cases of condylar fractures in which reduction of the dislocated condyle is very difficult or virtually impossible.

• Restorative Dentistry and Endodontics
• /
• 제41권2호
• /
• pp.83-90
• /
• 2016

Objectives: This study was evaluated the marginal microleakage of two different adhesive systems before and after aging with two different dye penetration techniques. Materials and Methods: Class V cavities were prepared on the buccal and lingual surfaces of 48 human molars. Clearfil SE Bond and Single Bond (self-etching and etchand-rinse systems, respectively) were applied, each to half of the prepared cavities, which were restored with composite resin. Half of the specimens in each group underwent 10,000 cycles of thermocycling. Microleakage was evaluated using two dimensional (2D) and three dimensional (3D) dye penetration techniques separately for each half of each specimen. Data were analyzed with SPSS 11.5 (SPSS Inc.), using the Kruskal-Wallis and Mann-Whitney U tests (${\alpha}=0.05$). Results: The difference between the 2D and 3D microleakage evaluation techniques was significant at the occlusal margins of Single bond groups (p = 0.002). The differences between 2D and 3D microleakage evaluation techniques were significant at both the occlusal and cervical margins of Clearfil SE Bond groups (p = 0.017 and p = 0.002, respectively). The difference between the 2D and 3D techniques was significant at the occlusal margins of non-aged groups (p = 0.003). The difference between these two techniques was significant at the occlusal margins of the aged groups (p = 0.001). The Mann-Whitney test showed significant differences between the two techniques only at the occlusal margins in all specimens. Conclusions: Under the limitations of the present study, it can be concluded that the 3D technique has the capacity to detect occlusal microleakage more precisely than the 2D technique.

• Restorative Dentistry and Endodontics
• /
• 제5권1호
• /
• pp.29-34
• /
• 1979

The purpose of this study was to measure thermal expansions of dental investments, Biovest(Casting Investment. Dentsply International INC, U.S.A.), Multi-Best (Use for all dental chrome-cobalt alloys, The Ransom & Randolph Co. U.S.A.), Kerr(Inlay Investment. Sybron Kerr, U.S.A.), O. K. (Inlay Investment. Shofu Dental MFG, Co. Japan), Whip-Mix (Cristobalite Inlay Investment. Whip-Mix Corporation. U.S.A.). Thermal expansion of specimens(5mm in diameter and 50mm in length) was measured by a dilatometer at the temperature range from $20^{\circ}C$ to $700^{\circ}C$ by comparing expansion between standardized quartz and experimental specimens with heating rate about $300^{\circ}C$/hr. The following results were obtained. 1. The coefficient of thermal expansion of Biovest was $15{\times}10^{-6}/^{\circ}C$ in the water powder ratio 18/100 and $14{\times}10^{-6}/^{\circ}C$ in the water powder ratio 28/100. Those of Multi-Best were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 14/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 24/100. 2. The coefficient of thermal expansion of Kerr were $17{\times}10^{-6}/^{\circ}C$ in the water powder ratio 38/100 and $14{\times}10^{-6}/^{\circ}c$ in the water powder ratio 48/100. Those of O. K. were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 33/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 43/100 3. The coefficient of thermal expansion of Whip-Mix were $14{\times}10^{-6}/^{\circ}C$ in the water powder ritio 40/100 and $12{\times}10^{-6}/^{\circ}c$ Fein the water powder ratio 50/100. Those of Hi-Heat were $11{\times}10^{-6}/^{\circ}c$ in the water powder ratio 28/100 and $10{\times}10^{-6}/^{\circ}c$ in the water powder ratio 38/100.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제17권4호
• /
• pp.253-263
• /
• 2017

Regardless of whether it is acute or chronic, the assessment of pain should be simple and practical. Since the intensity of pain is thought to be one of the primary factors that determine its effect on a human's overall function and sense, there are many scales to assess pain. The aim of the current article was to review pain intensity scales that are commonly used in dental and oral and maxillofacial surgery (OMFS). Previous studies demonstrated that multidimensional scales, such as the McGill Pain Questionnaire, Short form of the McGill Pain Questionnaire, and Wisconsin Brief Pain Questionnaire were suitable for assessing chronic pain, while unidimensional scales, like the Visual Analogue Scales (VAS), Verbal descriptor scale, Verbal rating scale, Numerical rating Scale, Faces Pain Scale, Wong-Baker Faces Pain Rating Scale (WBS), and Full Cup Test, were used to evaluate acute pain. The WBS is widely used to assess pain in children and elderly because other scales are often difficult to understand, which could consequently lead to an overestimation of the pain intensity. In dental or OMFS research, the use of the VAS is more common because it is more reliable, valid, sensitive, and appropriate. However, some researchers use NRS to evaluate OMFS pain in adults because this scale is easier to use than VAS and yields relatively similar pain scores. This review only assessed pain scales used for post-operative OMFS or dental pain.