Resin Teeth Research Articles

Protocol for clinical articulation of complete dentures in maximum intercuspation

The aim of the study was to evaluate the application of clinical protocol for articulation of complete dentures (CDs) in maximum intercuspation (MIP) under the control of T-Scan 8 system and articulation paper. The study involved 32 edentulous patients, aged from to years (mean age 71±9.28 years), who had been treated with complete dentures in the Faculty of Dental Medicine, Medical University-Sofia. Two sets of Superacryl Plus plastic CDs with Flat Ac Acrylic resin teeth were made for each patient according to the classic methodology. The first set of CDs (group 1) was articulated in the MIP under the control of articulation paper only, while the second set of CDs (group 2) was articulated according to a clinical protocol, in which a digital T-Scan 8 analysis and an articulation paper registration were combined. In group 1, occlusion time (OT) higher than normal (56.2%); force outliers (81.25%); and reduced vertical dimension of occlusion (43.8%) were found, resulting in total occlusal force of 100% in the MIP in only 15.67% of the cases. In group 2, OT higher than normal was found in only one set of CDs (3.12%) and force outliers in four sets of CDs (12.5%). The strongest contacts were 2.03±1.57 per denture and most distally situated, and the total force in the MIP averaged 99.39±0.66%. Thus clinical protocol for articulation of CDs under digital control in combination with articulation paper allows the proper selection of contacts in articulation of dentures in the MIP by overcoming the subjective factor.

In vitro investigation of the impact of remaining tooth structure on the tensile failure loads of overdenture copings.

BackgroundThe purpose of this in vitro study was to evaluate the impact of the remaining tooth structure on the retention of overdenture cast metal copings.Material and MethodsA freshly extracted intact mandibular human canine (length 25 mm) was selected and endodontically treated. An incisal reduction of 4 mm with no ferrule preparation was performed and a post space of 12 mm was created. By using polyvinyl siloxane duplication material and autopolymerizing polymethylmethacrylate resin, ten resin teeth analogs (control group) were obtained. A second set of ten resin teeth analogs (group 1) was created by preparing on the original natural tooth a 360o ferrule design of 1 mm in height and by using the same procedural technique. The canine was further reduced by an additional 1 mm, resulting in a ferrule of 2 mm in height, measured from the initial incisal reduction, thus a third set of ten resin teeth analogs (group 2) was created. For every tooth analog in all groups a dome-shaped metal coping was cast and luted with a glass ionomer cement. All specimens were subjected to tensile load testing until decementation occurred.ResultsThe specimens in the control group exhibited a mean failure load of 87.21 ± 18.26 N, while the 1 mm ferrule group recorded a higher mean failure load of 125.43 ± 8.79 N and the 2 mm ferrule group recorded the highest mean failure load of 146.12 ± 23.38 N. One-way ANOVA revealed significant differences (F= 28.04, p<0.001) in the tensile failure loads between all of the groups being tested.ConclusionsThe metal copings with a 2 mm ferrule design exhibited the highest retention values, followed by the 1 mm ferrule and the no ferrule design, with the differences among them being statistically significant. Key words:Ferrule effect, In vitro study, Metal copings, Overdenture, Tensile stress.

Evaluation and comparison of the effect of different chemical surface treatments (monomethyl methacrylate monomer, dichloromethane, and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer solvent) on the shear bond strength of acrylic resin teeth to the heat cure denture base resin

Background: Prefabricated acrylic resin teeth for dentures were started in use from 1940. About 26%–33% of denture repairs are the result of debonded teeth which cause distress and increased cost for patients. Taking into consideration the importance of properly bonded teeth to denture bases, this in-vitro study was designed to evaluate and compare the effects of three different chemicals on shear bond strength of cross-linked acrylic resin teeth with heat cure denture base resin. Methodology: This study was carried out in Government Dental College and Hospital, Mumbai, in collaboration with the Indian Institute of Technology, Powai. For the purpose of the study, 100 maxillary right central incisors, made up of heat cure cross-linked acrylic resin (MAARC) were collected. The wax samples were randomly divided according to systematic random sampling and coded into four groups of 25 samples each. The four groups were the control group, the monomethyl methacrylate group, the dichlormethane group and trichloroethane+ monomethyl methacrylate group. Results: The control group had lowest value for shear bond strength ranging from 117 N to 181 N with a mean of 147.8 N, whereas 1:1 mixture of v/v of 30% trichloromethane and monomethyl methacrylate had the highest value ranged from 145 N to 310 N with the mean value of 224.88 N. Among the chemical solvents used, monomethyl methacrylate had the lowest shear bond strength ranging from 120 N to 256 N with the mean value 187.32 N. Conclusion: The study concluded that chemical surface treatment of cross-linked acrylic teeth with 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer gave the highest strength.

Effect of surface treatments on the bond repair strength of resin composite to different artificial teeth

The purpose of this study was investigate the influence of different surface treatments on the shear bond strength of two different type of artificial resin teeth repaired with composite resin. Fifteen (15) artificial teeth of each material (CR-composite resin and AR-acrylic resin) were divided into four parts and then embedded in acrylic resin. After, the teeth were separated into eight groups according to the surface treatments prior to the repair: control group (c), adhesive application (a), sandblasting (S) and sandblasting followed by adhesive application (Sa). Next, a composite resin cylinder (Ø = 0.95 mm e h = 2 mm) simulating a repair was built onto each surface. The specimens were submitted to a microshear bond test after 24 h, using a universal testing machine (1 mm/min, 50 kgf) until fracture. The data was subjected to two-way analysis of variance (ANOVA) and Tukey test, with a significance level of 5%. ANOVA showed statistical difference for the interaction artificial teeth material* surface treatment (p = 0.001). CR teeth (29.79 ± 11.54 MPa) showed higher bond strength mean values than AR (18.48 ± 9.73 MPa). Regardless the artificial teeth material, Sa (36.92 ± 6.16 MPa) treatment showed the higher bond strength values. The highest bond strength value was found in CRSa (45.93 ± 7.13 MPa) and the lowest was found in ARc (5.38 ± 0.90 MPa). Based on the results, tooth material should be taken in account in order to choose the best surface treatment and achieve suitable bond strength values when a repair is necessary. For artificial teeth in acrylic resin, applying an adhesive system is the best procedure, with or without sandblasting the alumina particles. However, for artificial teeth in composite resin, an association of sandblasting followed by applying an adhesive system showed more promising bond strength values.

In vitro 3D and gravimetric analysis of removed tooth structure for complete and partial preparations

PurposeTo quantify and to compare a gravimetric and three-dimensional (3D) analysis of the removed tooth structure for different complete crown preparations. MethodsA total of 80 molar resin teeth and 8 preparation finishing lines were chosen: 1 for metal ceramic crowns (MCC); 3 for zirconia all-ceramic crowns: knife edge (ZirKnE), chamfer (ZirCha), and shoulder (ZirSho); 4 for lithium disilicate: light chamfer (LDLCha), chamfer (LDCha), shoulder (LDSho) and table top. Teeth were individually weighed to high precision and then prepared following the preparation guidelines. The teeth were reweighed after preparation, and the amount of structural reduction was calculated. In addition, all teeth were scanned before and after preparation, and the 3D volume of removed dental tissue was calculated, superimposing the two .stl files, as a difference of the volumes before and after the preparation. Kruskal–Wallis statistical analysis was carried out to determine significant differences among the groups with a significance level of p<0.05. ResultsBoth analyses showed that LDLCha, ZirKnE and table-top preparations produced the smallest amount of removed structure, whereas the preparations for MCC, ZirSho and LDSho were more destructive. For MCC, 2.6 times more tooth structure must be removed than for table top. ZirKnE was 17.82% and LDLCha was 21.51% more conservative than MCC. The data obtained through the volumetric method were similar with those obtained by gravimetric analysis. ConclusionsZirKnE, LDLCha, and table-top preparations produced the least amount of tooth tissue removal. Three-dimensional volumetric analysis can be a possible alternative to gravimetric analysis.

Development of a dental handpiece angle correction device

BackgroundPreparation of a uniform angle of walls is essential for making an ideal convergence angle in fixed prosthodontics. We developed a de novo detachable angle-correction apparatus for dental handpiece drills that could help the ideal tooth preparation.MethodsWe utilized a gyro sensor to measure the angular velocities to calculate the slope of an object by integrating the values, acceleration sensor to calculate the slope of an object by measuring the acceleration relative to gravity, and Kalman filter algorithm. Converting the angulation of the handpiece body to its drill part could be performed by a specific matrix formulation set on two reference points (2° and 6°). A flexible printed circuit board was used to minimize the size of the device. For convergence angle investigation, 16 volunteers were divided randomly into two groups for performing tooth preparation on a mandibular first molar resin tooth. All abutments were scanned by a 3D scanner (D700®, 3Shape Co., Japan), the convergence angle and tooth axis deviation were analyzed by a CAD program (SolidWorks 2013®, Dassault Systems Co., USA) with statistical analysis by Wilcoxon signed-rank test (α = 0.05) using SPSS statistical software (Version 16.0, SPSS Inc.).ResultsThis device successfully maintained the stable zero point (less than 1° deviation) at different angles (0°, 30°, 60°, 80°) for the first 30 min. In single tooth preparation, without this apparatus, the average bucco-lingual convergence angle was 20.26° (SD 7.85), and the average mesio–distal (MD) convergence angle was 17.88° (SD 7.64). However, the use of this apparatus improved the average BL convergence angle to 13.21° (SD 4.77) and the average MD convergence angle to 10.79° (SD 4.48). The angle correction device showed a statistically significant effect on reducing the convergence angle of both directions regardless of the order of the directions.ConclusionsThe angle correction device developed in this study is capable of guiding practitioners with high accuracy comparable to that of commercial navigation surgery. The volume of the angle correction device is much smaller than that of any other commercial navigation surgery system. This device is expected to be widely utilized in various fields of orofacial surgery.

Effect of preparation design on marginal and internal adaptation of translucent zirconia laminate veneers.

This study investigated the effect of preparation design on the marginal and internal adaptation of laminate veneers (LVs) fabricated from translucent zirconia. Thirty-three resin teeth were prepared for LVs of three designs: window preparation (WP); incisal shoulder preparation (ISP); and incisal palatal chamfer preparation (IPP). Marginal adaptation was evaluated by measuring the vertical discrepancy between the LV margin and the finish line at 60 points. The internal adaptation was assessed by measuring the internal space width as the distance between the LV and the tooth at cervical, central, and incisal sites after sectioning. At the incisal, mesial, and distal sites, mean marginal discrepancies were significantly lower in the WP group than in the other two groups; the IPP group had the highest marginal discrepancies. At incisal sites, the median internal space was significantly higher in the IPP group than in the WP and ISP groups and higher in the ISP group than in the WP group. At the incisal site, marginal and internal adaptations were better for the non-overlap translucent zirconia LV design (WP) than for the overlap designs (ISP and IPP). The characteristics of the translucent zirconia LVs used in the present study indicate acceptable clinical performance.

3D Printing of Resin Material for Denture Artificial Teeth: Chipping and Indirect Tensile Fracture Resistance.

3D printing of denture artificial teeth with resin materials is worthy of study in a novel way. This study evaluated chipping and indirect tensile fracture resistance of 3D printing resin material (Dentca 3D printing denture teeth resin) compared with conventionally prefabricated resin denture teeth (Premium-8, Surpass, SR-Orthosit-PE, and Preference). One hundred tooth specimens were prepared for testing. The 3D printed tooth specimens were printed at a 50 µm layer thickness with methacrylate-based photopolymerized resin by stereolithography 3D printing. Chipping and indirect tensile fracture tests were conducted at a speed of 1 mm/min until fracture. The indirect tensile fracture loads of the 3D printed resin teeth were higher than those of Premium-8, Surpass, and SR-Orthosit-PE, and lower than those of Preference teeth. Regarding chipping resistance, the 3D printed resin teeth were not different from Surpass and SR-Orthosit-PE, and were lower than Premium-8 and Preference teeth. The 3D printed resin teeth exhibited vertical fracture of the loaded cusp without deformation in chipping. The 3D printed resin teeth showed simultaneous fracture of two cusps in indirect tensile fracture, unlike other teeth. The results of this study suggest that 3D printing technology using resin materials provides adequate fracture resistance for denture artificial tooth use.

Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the All-on-Four concept.

More research is needed on the study of new materials for fixed prosthetic implant-supported rehabilitations. The purpose of this study was to report the short-term outcome of full-arch implant-supported fixed hybrid polyetheretherketone (PEEK)-acrylic resin prostheses and the all-on-four concept. This prospective cohort clinical study included 37 patients (29 women, eight men) with an average age of 60 years (range: 38-78 years) with 49 full-arch hybrid PEEK-acrylic resin prosthesis supported by implants through the all-on-four concept. Primary outcome measures were prosthetic survival. Two patients with two maxillary prostheses were lost to follow-up. One patient with a double full-arch rehabilitation fractured the mandibular PEEK framework, rendering a 98% prosthetic survival rate. No implants were lost. The average (SD) marginal bone remodeling after 1 year of follow-up was 0.37 mm (0.58 mm). Technical complications concerning the veneer adhesion occurred in six patients and were resolved in all patients (with exception of the patient with prosthetic failure) through the creation of mechanical retentions and changing the bonding primer. Mechanical complications occurred in three patients and five prostheses consisting in prosthetic screw loosening (n = 2 patients) and fracture of the acrylic resin teeth (the patient with a prosthetic failure). Within the limitations of this study, the results suggest that hybrid polymer (PEEK)-acrylic resin prostheses supported by implants for full-arch rehabilitation may represent a valid treatment option, still requiring longer-term validation.

THE EFFECT OF GREEN TEA EXTRACT AS A MATRIX METALLOPROTEINASE INHIBITOR ON THE BOND STRENGTH OF RESIN COMPOSITE

Objective: the aim of the study was to investigate the effect of epigallocatechin- 3-gallate (EGCG) from green tea extract as collagen cross linking agent on dentin bond durability at differ­ent aging times. Materials and Methods: thirty sound premolars were used, they were divided into two groups (15 each) according to the pretreatment protocol. Mid-coronal flate dentine surface was obtained. Group A had no pretreatment done, where bonding agent was placed as the manufacturer instruc­tions. Group B had EGCG pre-adhesive conditioner rubbed before bonding procedures. Bond­ing procedure was followed by the application of nano-hybrid resin composite in tygon tubes for micro-shear bond strength measurement. Each group was further subdivided in to three subgroups according the aging protocol, where T1 specimens were stored for 24 hours, T2 they were stored for 6 months and T3 they were thermocycled. Results: All data was statistically analyzed, where group B showed statistically significant higher mean bond strength values (19.5 MPa) than group A (12.1MPa) regardless of the aging pro­tocol. There was statistically significant change in micro-shear bond strength results due to aging regardless of the pretreatment. Where T1 revealed the highest mean values (17.1MPa) followed by T3 ( 15.5 MPa) and the lowest mean values were reported with group T2. There was a statistically significant decrease in mean micro-shear bond strength from T1 to T2 followed by non-statisti­cally significant change in micro-shear bond strength from T2 to T3. The mean micro-shear bond strength at T3 showed statistically significantly lower value compared to T1 value. Conclusion: Green tea extracts (EGCG) is a powerful source of proanthocyanidin that has proved to be a good biological substitute as a cross-linker for preserving the integrity of dentin, enhancing the tooth resin composite inter-face when compared with universal adhesives present now a days in the market. Recommendation: More long term clinical and laboratory studies are needed to assess the durability of adhesives

Novel magnetic nanoparticle-containing adhesive with greater dentin bond strength and antibacterial and remineralizing capabilities

ObjectivesA nanoparticle-doped adhesive that can be controlled with magnetic forces was recently developed to deliver drugs to the pulp and improve adhesive penetration into dentin. However, it did not have bactericidal and remineralization abilities. The objectives of this study were to: (1) develop a magnetic nanoparticle-containing adhesive with dimethylaminohexadecyl methacrylate (DMAHDM), amorphous calcium phosphate nanoparticles (NACP) and magnetic nanoparticles (MNP); and (2) investigate the effects on dentin bond strength, calcium (Ca) and phosphate (P) ion release and anti-biofilm properties. MethodsMNP, DMAHDM and NACP were mixed into Scotchbond SBMP at 2%, 5% and 20% by mass, respectively. Two types of magnetic nanoparticles were used: acrylate-functionalized iron nanoparticles (AINPs); and iron oxide nanoparticles (IONPs). Each type was added into the resin at 1% by mass. Dentin bonding was performed with a magnetic force application for 3min, provided by a commercial cube-shaped magnet. Dentin shear bond strengths were measured. Streptococcus mutans biofilms were grown on resins, and metabolic activity, lactic acid and colony-forming units (CFU) were determined. Ca and P ion concentrations in, and pH of biofilm culture medium were measured. ResultsMagnetic nanoparticle-containing adhesive using magnetic force increased the dentin shear bond strength by 59% over SBMP Control (p<0.05). Adding DMAHDM and NACP did not adversely affect the dentin bond strength (p>0.05). The adhesive with MNP+DMAHDM+NACP reduced the S. mutans biofilm CFU by 4 logs. For the adhesive with NACP, the biofilm medium became a Ca and P ion reservoir. The biofilm culture medium of the magnetic nanoparticle-containing adhesive with NACP had a safe pH of 6.9, while the biofilm medium of commercial adhesive had a cariogenic pH of 4.5. SignificanceMagnetic nanoparticle-containing adhesive with DMAHDM and NACP under a magnetic force yielded much greater dentin bond strength than commercial control. The novel adhesive reduced biofilm CFU by 4 logs and increased the biofilm pH from a cariogenic pH 4.5–6.9, and therefore is promising to enhance the resin–tooth bond, strengthen tooth structures, and suppress secondary caries at the restoration margins.

Stress distribution in tooth resin core build-ups with different post-end positions in alveolar bone level under two kinds of load directions

This study aimed to evaluate influence of different post-end positions in alveolar bone level on stress distributions in resin-core build-up tooth under different load directions. Three-dimensional mathematical models of a root-filled mandibular premolar tooth were constructed. Resin post and core were built-up with six post lengths: 0, 1, 2, 3, 4, and 6 mm. Finite element analysis calculated stress distributions with oblique load of 400 N to buccal cusp 45 degree from buccal side or from lingual side. The 3 mm-post length (post-end position equal to cancellous bone level) caused highest equivalent stress of post-end compared with the shorter or longer post length. When change of load direction, the direction of maximum shear stress became completely opposite at mesiodistal cervical edge of core-part without a change of the magnitude. Changing shear stress direction would increase risk of debonding at mesiodistal cervical edge.

Evaluation of the fit of metal copings fabricated using stereolithography

Statement of problemRapid prototyping, including stereolithography (SLA), is a more recent technique for fabricating metal frameworks than the conventional lost-wax technique. However, investigations of the marginal discrepancies and internal spacing of cobalt-chromium (Co-Cr) metal copings fabricated using SLA are lacking. PurposeThe purpose of this in vitro study was to evaluate the clinical acceptability of the marginal discrepancies and internal spacing of Co-Cr metal copings fabricated using the SLA technique. Material and methodsA resin tooth of a maxillary right first premolar was prepared with a deep chamfer margin for a metal–ceramic crown. Titanium master dies were milled after scanning the prepared tooth (n=45). In conventional lost wax group (group LW), the conventional lost-wax technique was used to fabricate Co-Cr metal copings (n=15). In milling group (group MC), a computer-aided design (CAD) system was used to design the metal copings, which were milled from Co-Cr alloy (n=15). The CAD system was also used to design the metal copings in a 3D-printed group (group SL), and Co-Cr metal copings were cast from resin patterns fabricated using the SLA device (n=15). Marginal discrepancies and internal spaces were measured using an optical microscope at ×100 magnification at 11 reference points. The values were analyzed statistically with 1-way analysis of variance (α=.05). ResultsThe mean (±SD) overall space was 63.2 ±16.6 μm for group LW, 70.2 ±15.5 μm for group SL, and 130.3 ±13.8 μm for group MC. The overall spaces differed significantly between group MC and the other 2 groups (P<.05). The marginal discrepancy and internal spaces were significantly larger in group MC than in groups LW and SL. (P<.05). Occlusal spaces differed significantly among the 3 study groups (P<.05). ConclusionsCo-Cr metal copings fabricated using an SLA technique showed clinically acceptable marginal discrepancies and internal spaces. These spaces did not differ significantly from those obtained with the conventional lost-wax technique.

Biodegradation of resin–dentin interfaces is dependent on the restorative material, mode of adhesion, esterase or MMP inhibition

ObjectiveTo measure the effect of simulated human salivary esterases (SHSE) and metalloproteinases (MMP) inhibition on the integrity of restoration–tooth interfaces made from traditional or polyacid-modified resin composites bonded to human dentin by either total-etch or self-etch adhesives. MethodsResin–dentin specimens, made from traditional (Z250) or polyacid-modified (Dyract-eXtra) composites were bonded to human dentin using total-etch (TE-Scotchbond) or self-etch (SE-EasyBond) adhesives. TE was applied with or without the MMP inhibitor galardin. Specimens were incubated in phosphate-buffer or SHSE (37°C/pH=7.0) for up to 180 days, then suspended in a continuous flow biofilm fermenter cultivating biofilms of Streptococcus mutans UA159. Interfacial bacterial penetration, biofilm biomass and viability were measured by confocal laser scanning microscopy and biomarker dyes and used as interfacial biodegradation markers. ResultsAll specimens showed increased biofilm penetration and biomass with time regardless of incubation condition. SHSE increased bacterial penetration in all experimental samples after 180days (p<0.05). Galardin reduced interfacial bacterial ingress and bacterial biomass vs. non-MMP-inhibited TE-bonded specimens (p<0.05). TE interfaces showed lower interfacial bacterial biomass vs. SE after 90-day and 180-day (p<0.05). Dyract-eXtra specimens showed lower bacterial cell viability within the interface vs. Z250 (p<0.05). SignificanceThe biodegradation of resin–tooth interfaces is accelerated by esterases, modulated by MMP inhibition and is dependent on the material’s chemistry and mode of adhesion. The in vitro bacterial growth model used in this study facilitates the elucidation of differences in interfacial integrity and biostability between different materials and techniques and is suitable for assessment of their performance prior to clinical evaluation.

義歯床用レジンの開発に関する研究 : (第1報)人工歯の移動と適合性について

義歯床用レジンの開発に関する研究 : (第1報)人工歯の移動と適合性について

Efficacy of Various Pretreatments on the Bond Strength of Denture Teeth to Denture Base Resins.

This in vitro study evaluated the shear bond strength (SBS) of heat-cured denture base resin (PMMA) to acrylic resin teeth treated with different pretreatments, especially laser irradiation of different powers (1-4 W). The acrylic resin teeth were separated into seven groups (n = 10) for the following different pretreatments: control group (no surface treatment) (G1), grinding with a tungsten carbide bur (G2), sandblasting (G3), and erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation at 1 W, 2 W, 3 W, 4 W output powers in (G4-7), respectively. Test specimens were produced according to the PMMA manufacturers' instructions and were subjected to a SBS test at a crosshead speed of 1 mm/min until fracture. Debonded surfaces were evaluated by a stereomicroscope for the type of failure. SEM (scanning electron microscope) analyses were done to estimate the surface changes of the acrylic resin teeth. The data were submitted using a one-way ANOVA and post hoc Tukey-Kramer multiple comparison tests (p = 0.05). The highest bond strength was obtained in G3, and similar SBS values were considered in other groups, and no significant differences were found among the surface treatments and the control group (p < 0.05). All groups had a high percentage of adhesive failures. Laser irradiations promote surface topography alterations. However laser irradiation of the adhesive surface was found ineffective. The SBS of acrylic resin teeth to a PMMA denture base material is independent of the surface pretreatments Er,Cr:YSGG laser irradiation, sandblasting, and grinding with a carbide bur. All the surface treatments provided a similar bond between the acrylic denture base and the teeth.

표면처리가 인공치와 의치상의 전단결합강도에 미치는 영향

본 연구에서는 열중합 의치상과 인공치, 자가중합 의치상과 인공치의 치조면에 유지홀과 프라이머를 도포하여 전단결합 강도에 미치는 영향을 비교해보고자 하였다.BR Trubyte Biotone 레진치는 상악 1대구치를 선택하여 총 80개 치아를 준비하였다. 준비된 치아는 치조면을 덴쳐바를 사용하여 평평하게 연마하였고, 연마된 시편은 실리콘 몰드(직경 30 mm, 높이 23 mm) 중앙에 인공치를 위치시키고 투명 아크릴 레진(ortho jet, lang dental, USA)으로 포매하였다. 이중 40개는 치조면 중앙부위에 fissur bur #701을 이용하여 유지홀을 형성하였다. 인공치에 의치상 레진 접합을 위해 테프론으로(지름 6 mm, 높이 3 mm) 몰드를 형성 후 파라핀 왁스를 채워 통상적인 매몰을 하였다. 각각의 의치상 레진은 표면 처리 후 제조사의 지시대로 레진 전입하였다.BR 열중합형 레진을 이용한 전단결합강도는 인공치아에 유지홀과 프라이머 도포를 하였을 때 가장 높은 강도값(36.2 MPa)을 나타내었다. 자가중합형 레진을 이용한 전단결합강도는 인공치아에 프라이머를 도포 하였을 때 가장 낮은 값(11.8 MPa)을 나타내었다. 열중합형 의치상과 인공치의 결합에서는 복합 파절 양상을 보였고, 자가중합형 의치상과 인공치의 결합에서는 접착파절 양상을 보였다.

An alternative digital workflow for fabricating a mandibular implant-supported complete fixed dental prosthesis with limited restorative space: A clinical report

This clinical report describes the prosthetic rehabilitation of a patient with a mandibular implant-supported complete fixed dental prosthesis with limited interocclusal restorative space. The problem was manifested by repeated fractures of the acrylic resin teeth and distortion of the supporting framework. The definitive restoration included a custom computer-aided design and computer-aided manufacturing (CAD-CAM) titanium framework with the lingual cusps and most of the occlusal table of the mandibular posterior teeth milled in titanium as part of the framework. An esthetic CAD-CAM milled denture base along with teeth was bonded over this framework.

Effect of surface treatment on shear bond strength of artificial teeth to the denture base

Fracture or debonding of plastic teeth from the denture base are common clinicalproblems, the optimal combination of acrylic resin denture teeth and microware cureddenture base resin is not well known .one hundred and twenty teeth (florident, acrylicteeth cross-linked, china) were prepared and cured by heat cured (AkrilEks, heatcuringresin for denture powder liquid, GuLSA LTD. Izmir-Turkey), and microwarecured (Acron mc, microwave-curing denture base resin powder liquid, GCLABTechnologies inc. Alsip,IL60803 Japan) acrylic resin were used, then the teeth weredivided into six groups and treated with different surface treatment, the first groupreceived no further treatment(control); the second group treatment with diatoricpreparation; the third group treated with thinner(Turpentine-DYNA CoAT, Thinner,Netherlands); the fourth group treated with tone(Propanone, Acetone, England 99%Purity-Analyer); the fifth group were diatoric conditioned with acetone; the sixthgroup were diatoric conditioned with thinner;(2nd group, 5th group and 6th group hadbeen a cutting mesiodistal retention grooves 2mm deep and 3mm wide acute intoridge lap in acrylic resin teeth. One hundred and twenty specimens were divided intotwo groups, first one was processed by conventional method and the other oneprocessed by microwave method and then tested by instron universal testing machine(instron corporation 1195,canton mass).The results showed than microwave-curedresin has a significant lower shear bond strength(SBS) mean values than water bathcuredresin to all denture teeth types. All surface treatment application improvedthe(SBS) significantly level at(p value &lt; 0.05), while the sixth group (diatoricconditioned with thinner) showed the highest(SBS) than other group. The types ofacrylic denture resin, surface treatment and curing technique influenced the shearbond strength of the tooth to the base the results of this study influenced the shearbond strength of the tooth to the base. The results of this study indicate that diatoriccondition with thinner may be recommended to be applied on the denture ridge lapprior to denture base processing.

28. Discolouration of acrylic resin teeth due to cigarette smoke

28. Discolouration of acrylic resin teeth due to cigarette smoke