Effect of UV aging on translucency of currently used esthetic CAD-CAM materials.

OBJECTIVES: To evaluate the relative translucency parameter (RTP) values of computer-aided design (CAD)-computer-aided manufacturing (CAM) materials after UV aging. MATERIALS AND METHODS: 70 specimens (n = 10) of Bruxzir Anterior (BA); E.max Cad (EC); Lava Ultimate (LU); Cerasmart (CE); Vita Enamic (VE); Vita Suprinity (VS); Vita Mark II (VM) were prepared (1 mm ± 0.01 mm). Color measurements were performed using a spectrofotometer (VITA Easyshade). RTP values of the specimens before (RTP1 ) and after UV aging (RTP2 ) were evaluated. Statistical analyses were done with repeated measurements of two-way-ANOVA with Bonferroni test (P < 0.05). RESULTS: Evaluating RTP1 and RTP2 values; significant differences were found (P < 0.05). There were no significant difference between the RTP1 values of CE and VS (P = 0.779); EC and VM (P = 0.952); VM and LU (P = 0.995); EP and LU (P = 0.653). Evaluating RTP2 values; VE and BA were found significantly different from the others (P < 0.05). For all evaluated groups TP values decreased after UV aging (P < 0.05). The most RTP reduction was observed for LU; while VM and EC were less affected. CONCLUSION: Glass ceramic VE showed the highest RTP and zirconia-based BA was the most opaque restorative CAD-CAM material. UV aging caused the CAD-CAM materials get more opaque. CLINICAL SIGNIFICANCE: In cases where translucency is needed chosing VE would give better esthetic results; while zirconia-based BA should be used if more opaque restoration is needed. Clinicians should be aware of that restorations get more opaque after usage.

Color relationships of natural anterior teeth: An In vivo study.

OBJECTIVES: To investigate the color relationships between the anterior teeth in vivo. MATERIALS AND METHODS: A total of 640 volunteers (age: 18-22) participated in the study. The color measurements of left maxillary and mandibular central, lateral, and canine were performed using a colorimeter. Color differences were calculated according to the CIE L*a*b* (ΔE*) and CIEDE2000 (ΔE00*) system. The National Bureau of Standards (NBS) ratings were also evaluated. Statistical analyses were performed using two-way ANOVA and Fisher's exact test (P < 0.05). RESULTS: Significant differences were found between the L*, a*, b*, and ΔE* values (P < 0.05), except for mandibular central and lateral. ΔE* values were found between 1.5 ΔE* (mandibular central-mandibular lateral) and 8.1 ΔE* (maxillary central-maxillary canine). While the highest L* (80.5) and the least b* (15.1) values were obtained for mandibular central, the mean L* (73.6) and the mean b* values (21.3) were obtained for the maxillary canine. a* value was found to be highest for the mandibular lateral (1.1) and the least for the maxillary central (-0.2) teeth. NBS values were between 1.3 and 7.4 units, and only mandibular central and mandibular lateral teeth exhibited "almost the same" color values, while the other teeth exhibited "slightly different," "very different," or "remarkably different" color values. CONCLUSION: Anterior maxillary and mandibular teeth exhibited "different" color values. Only mandibular incisors and mandibular laterals showed "almost the same" color. Canines were more dark/red/yellow for both mandible and maxilla. Centrals were more bright/green/yellow for maxilla and bright/green/blue for mandibular. Clinicians should select the color one by one for each tooth and be aware of their color relations for optimal esthetics.

Storing Tooth Segments for Optimal Esthetics.

OBJECTIVE: A fractured whole crown segment can be reattached to its remnant; crowns from extracted teeth may be used as pontics in splinting techniques. We aimed to evaluate the effect of different storage solutions on tooth segment optical properties after different durations. STUDY DESIGN: Sixty central incisor crowns were divided into 6 groups (n = 10); Group 1 was kept dry; Groups 2, 3, 4, 5, and 6 were placed in an isotonic solution, water, milk, saliva, and casein-phosphopeptide-amorphous-calcium-phosphate (CPP-ACP), respectively, for 30 min, 12 h, 1 day, 1 week, and 3 weeks. Color values were measured using a colorimeter. Data were analyzed with Kruskal-Wallis tests, Mann-Whitney U-tests, and Friedman Wilcoxon tests with Bonferroni stepwise corrections (p < 0.05). RESULTS: ΔE* values varied from 0.3 to 15.3 over the 3 week period. Group 1 demonstrated the greatest color changes over all durations; Group 6 exhibited the least. L*, a*, b*, and ΔE* values varied between time periods in all groups; the differences were significant (p < 0.01), except for L* and ΔE* values in Group 2 and a* values in Group 6 (p > 0.01). Comparing ΔE* values, Group 6 was significantly different from the other groups for all durations (p < 0.01), except Group 4. CONCLUSIONS: A CPP-ACP complex solution seems a good choice for tooth fragment storage. Milk and saliva solutions may cause perceptible color changes if tooth fragments are stored for 3 weeks before use.

Effects of protective resin coating on the surface roughness and color stability of resin-based restorative materials.

The aim of this study was to evaluate the effects of nanofilled protective resin coating (RC) on the surface roughness (Ra) and color stability (ΔE) of resin-based restorative materials (RM) (compomer (C), nanofilled composite (NF), and microhybrid composite (MH)) after being submitted to the ultraviolet aging (UV) method. Thirty-six specimens were prepared (n = 6 for each group). The Ra and (ΔE) values and SEM images were obtained before and after UV. Significant interactions were found among the RM-RC-UV procedures for Ra (P < 0.001). After the specimens were submitted to UV, the Ra values were significantly increased, regardless of the RC procedure (with RC; P < 0.01 for all, without RC; C (P < 0.01), NF (P < 0.001), and MH (P < 0.001)) for each RM. Significant interactions were found between the RM-RC (P < 0.001) procedures for the ΔE values. The ΔE values were increased in each group after applying the RC procedures (P < 0.001). Protective RC usage for RM could result in material-related differences in Ra and ΔE as with used UV method.

Do surface treatments affect the optical properties of ceramic veneers?

STATEMENT OF PROBLEM: Surface treatments may affect the optical properties of ceramic veneers before cementation. PURPOSE: The purpose of this study was to evaluate whether various surface treatments affect the optical properties of different types of ceramic veneers. MATERIAL AND METHODS: Disk-shaped ceramic veneers (N=280) were prepared from the IPS e.max Press, e.max CAD, Empress Esthetic, e.max Ceram, and Inline ceramic systems with 0.5-mm and 1.0-mm thicknesses. The ceramics were divided into 4 groups: no surface treatments; etched with hydrofluoric acid; airborne-particle abraded with 30-µm Al2O3; and irradiated with erbium:yttrium-aluminum-garnet laser. A translucent shade of resin was chosen for cementation. Color parameters were examined with a colorimeter. Statistical analyses were done with 3-way ANOVA and the Bonferroni test (P=.05). RESULTS: Significant interactions were noted between the surface treatments, ceramic type, and thickness for ΔE values (P=.01), and no significant interactions were noted for L* (P=.773), a* (P=.984), and b* (P=.998). The greatest color change occurred after airborne-particle abrasion with 0.5-mm-thick e.max Press (2.9 ΔE). Significant differences in ΔE values were found among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 0.5-mm-thick ceramics, except IPS Inline, and among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 1.0-mm-thick ceramics, except Empress Esthetic ceramics. CONCLUSIONS: The color change of the ceramics increased after the surface treatments, particularly as the ceramics became thinner.

Effect of different surface-cleaning techniques on the bond strength of composite resin restorations.

STATEMENT OF PROBLEM: Different techniques have been suggested for cleaning dentin surfaces after the removal of an interim prosthesis and before the application of a bonding agent. How different surface-cleaning techniques affect the bond strength of the composite resin restorations is not clear. PURPOSE: The purpose of this study was to investigate the effects of different surface-cleaning techniques on the bond strength of composite resin restorations and the surface topography of the prepared tooth surfaces. MATERIAL AND METHODS: The occlusal surfaces of 25 molars were ground until the dentin was exposed. A bonding agent and interim cement were applied on the teeth. The teeth were divided into 5 groups (n=5) according to the method used for surface-cleaning (microairborne-particle abrasion, alcohol, rubber-rotary instrument, desiccating agent, and control). Once the surfaces of the teeth had been cleaned, the same bonding material was applied to the teeth. A 5-mm-thick composite resin layer was built up. Each specimen was sectioned to microbars, and 6 centrally located beams were selected for microtensile testing (n=30) (1.10 ±0.10 mm). The data were statistically analyzed with 1-way ANOVA (1-sample Kolmogorov-Smirnov test). The Bonferroni test was used for significantly different groups (α=.05). One specimen from each group was observed under a scanning electron microscope and an atomic force microscope. Energy dispersive x-ray analysis also was performed. RESULTS: Bond strength values were in the following descending order: microairborne-particle abrasion, desiccating agent, alcohol, rubber-rotary instrument, control. Differences between the microairborne-particle abrasion group and the remainder of the groups, desiccating agent--rubber-rotary instrument, desiccating agent-control, alcohol--rubber-rotary instrument, and alcohol-control groups, were statistically significant (P<.05). The microairborne-particle abrasion group displayed the roughest surface and a different surface topography from the remainder of the groups. Increased aluminum was observed in the microairborne-particle abrasion group. CONCLUSIONS: Surface-cleaning techniques, except for the rubber-rotary instrument, increased the bond strength of composite resin. The roughest dentin surfaces and highest bond strength were achieved with the microairborne-particle abrasion technique.

Effect of antiasthmatic medication on the surface roughness and color stability of dental restorative materials.

OBJECTIVE: This study evaluated the effect of antiasthmatic medication on the surface roughness and color stability of dental restorative materials. MATERIALS AND METHODS: A total of 60 disc-shaped specimens were fabricated from glass ionomer (n = 20), composite resin (n = 20) and feldspathic porcelain (n = 20). Each material group was randomly divided into two subgroups (n = 10): (1) control group and (2) test group. Control groups of the specimens were kept in artificial saliva. Test groups were exposed to salbutamol sulfate (Ventolin Nebules) using an inhaler machine. Surface roughness measurements were done using a profilometry and color measurements were done with digital colorimetry at baseline and after inhalation and storing in artificial saliva. A two-way analysis of variance (ANOVA) and post-hoc Fisher's least significant difference test were used to compare the change in surface roughness and color. The confidence level was set at 95%. RESULTS: Inhaler treatment significantly increased the surface roughness and color change of glass ionomer and composite resin materials (p < 0.05), while the surface roughness and color of feldspathic porcelain was not changed after inhaler treatment (p > 0.05). CONCLUSION: The antiasthmatic inhaler medication (salbutamol sulfate) affected the surface roughness and color of composite resin and glass ionomer restorative materials.

Effect of ultraviolet aging on translucency of resin-cemented ceramic veneers: an in vitro study.

PURPOSE: The aim of this in vitro study was to evaluate the translucency of ceramic veneers cemented with light- or dual-cured resin cements after accelerated aging. MATERIALS AND METHODS: A total of 392 specimens were made of shade A1 with 0.5- and 1.0-mm thickness. Light-cured RelyX Veneer and dual-cured Maxcem Elite and Variolink II resin cements were applied on the porcelain discs with a thickness of 0.1 mm. Translucency parameter (TP) values of the ceramic veneers after cementation and UV aging test were evaluated. Statistical analyses were done with ANOVA and Tukey's tests and paired sample t-test (p < 0.05). RESULTS: All the resin cements affected the TP values of 0.5-mm-thick ceramic, while RelyX Veneer Tr (TP = 11.15; p = 0.608), Variolink II Tr (TP = 10.98; p = 0.55), and Maxcem Clear (TP = 11.81; p = 0.702) did not affect the translucency of 1-mm-thick ceramics (TP = 11.38). The aging process affected TP values of both ceramics and cemented ceramics, as the TP values decreased after aging. Among the TP values of opaque shade resin cements, there were significant differences between the "ceramic," "ceramic + RelyX Veneer WO," "ceramic + Variolink II WO," and "ceramic + Maxcem WO" variables for both 0.5 and 1 mm thicknesses (p < 0.05). There were no significant differences between "ceramic," "ceramic + RelyX Veneer Tr," "ceramic + Variolink II Tr," and "ceramic + Maxcem Clear" variables at 0.5 mm thickness, and there were no significant differences between "ceramic," "ceramic + RelyX Veneer Tr," and "ceramic + Variolink II Tr" variables after aging (p > 0.05). CONCLUSIONS: The TP of the same color of resin cements varied related to the type or brand. Aging caused both the ceramics and cemented ceramics to become more opaque.

Discoloration of provisional restorations after oral rinses.

PURPOSE: Oral rinses are widely used to promote periodontal health with provisional restorations during the interim period. The aim of this study was to compare the discoloration of provisional restoration materials with different oral rinses. MATERIAL AND METHODS: A total of 140 disc-shaped specimens (shade A2) (10 mm x 2 mm) were prepared from one PMMA-based (TemDent Classic(®)) and three different bis-acrylic-based (Protemp II(®), Luxatemp(®) and Fill-In(®)) provisional restoration materials (n=7). The color values (L*, a*, and b*) of each specimen were measured before and after exposure with a colorimeter, and the color changes (∆E) were calculated according to the CIE L*a*b* system. The specimens were immersed in each of the 4 oral rinses (alcohol-containing mouthwash, chlorhexidine, benzydamine HCl, benzydamine HCl and chlorhexidine) twice a day for 2 minutes. After 2 minutes of immersion in the oral rinses, the specimens were immersed in artificial saliva. The specimens were exposed to the oral rinses and the artificial saliva for 3 weeks. Two-way ANOVA, the Bonferroni test and the paired sample t-test were used for statistical analyses (p<0.05). RESULTS: Comparison of the discoloration from the oral rinses after immersion for three weeks revealed no significant differences (p>0.05). The lowest color change was observed in PMMA-based Temdent in all oral rinses (p<0.05). There were no significant differences between the bis-acryl composites after immersion in saliva or the mixture of benzydamine HCl and chlorhexidine and the alcohol-containing mouthwash for 3 weeks (p>0.05). After immersion in chlorhexidine, the color change values of Protemp II and Fill-in showed significant differences (p=0.018). Protemp II also showed less discoloration than the other bis-acryl composites, and this color change was statistically significant (p <0.05). For all oral rinses, the L* value decreased while b* values increased, and this color change was found to be statistically significant (p <0.05). A* values were found to be significantly higher with oral rinses (p<0.05), except Protemp II immersed in benzydamine HCl or alcohol-containing mouthwash. CONCLUSIONS: The type of the oral rinse did not affect the discoloration process. For long-term esthetic results, choosing MMA-based materials for provisional restorations appears to be more effective.

Effect of resin cement and ceramic thickness on final color of laminate veneers: an in vitro study.

STATEMENT OF PROBLEM: Different shades of resin cements may adversely affect the final color of translucent restorations, especially thin laminates. PURPOSE: The purpose of this study was to determine the effect of different types and shades of resin cement and different thicknesses and shades of IPS Empress Esthetic ceramics on the final color of laminate restorations. MATERIAL AND METHODS: A total of 392 disks were made with A1, A3, EO, and ET shades of IPS Empress Esthetic with 0.5-mm and 1-mm thicknesses. Two dual-polymerizable and 2 light-polymerizable resin cement systems from different manufacturers (a total of 13 shades) were selected for cementation (n=7). Similarly, with porcelain ingot shades A1 and A3, opaque and translucent shades were selected from the Rely X Veneer and Maxcem Elite cement systems. For the opaque and translucent shades of the Variolink II resin cement system, the highest and lowest (+3 and -3) and medium (0) shades of Variolink Veneer cement were included in the study. Color changes in the porcelain substructures after cementation were examined with a colorimeter, and color differences (ΔE) were calculated. The results were analyzed with Wilcoxon signed-ranks and Kruskal-Wallis tests (α=.05). RESULTS: The results indicated that the color of porcelain disks changed significantly after cementation (P<.001). Most of the color changes appeared after cementation with Variolink-3 Veneer in all porcelain shades. The smallest color change was obtained from Variolink II Tr in the EO shade of porcelain. The colors of the same shades of different resin cement systems were found at different coordinates in the CIE L*a*b* system. The final color difference (ΔE) of cemented veneers decreased when ceramic thickness increased. CONCLUSIONS: The type and shade of resin cement and the thickness and shade of the ceramic all influenced the resulting optical color of laminate restorations.

Antibacterial activity, surface roughness, flexural strength, and solubility of conventional luting cements containing chlorhexidine diacetate/cetrimide mixtures.

STATEMENT OF PROBLEM: The failure of fixed dental restorations is commonly associated with caries. The use of conventional luting cements containing antibacterial agents may overcome this problem. PURPOSE: The purpose of this study was to evaluate the antibacterial activity (ABA), surface roughness (Ra), flexural strength (FS), and solubility (SL) patterns of the conventional dental luting cements zinc phosphate (ZP), zinc polycarboxylate (PC), and glass ionomer (GIC) after the addition of 5% chlorhexidine diacetate/cetrimide (CHX+CT). MATERIAL AND METHODS: Antibacterial agents with a total concentration of 5% (2.5% CHX+2.5% CT) were added to antibacterial agent-free conventional luting cement powders (ZPC, PCC, and GICC) and designated as experimental groups (ZPE, PCE, and GICE). ABA against Streptococcus mutans (SM) and Lactobacillus casei (LB) was examined by using the agar diffusion test method. Ra, FS, and SL values were obtained after storage in distilled water at 37°C for 24 hours. The Kruskal-Wallis and Mann Whitney U with Bonferroni correction tests were used to test for agar diffusion (α=.05) and 2-way ANOVA and Fisher Least Significant Difference (LSD) test were used to measure Ra, FS, and SL (α=.05). RESULTS: The control groups exhibited limited ABA. With the exception of PCE>PCC on day 1 for SM, all experimental groups showed significantly greater and longer-lasting protection against SM and LB bacteria for up to 180 days than their controls (P<.05). Ra values decreased (ZPC>ZPE; P>.05, PCC>PCE; P<.05) except that GICE>GICC (P>.05) when compared with their individual controls. Control groups exhibited higher FS values than did the experimental groups (ZPC>ZPE; P<.05, PCC>PCE; P<.05, GICC>GICE; P>.05). The experimental groups exhibited higher solubilities than did their controls in the ZPC (P>.05) and GICC groups (P<.05) but were lower in PCC group (P<.05). CONCLUSIONS: Incorporating a 5% CHX+CT mixture into conventional dental luting cements and altering their Ra, FS, and SL values may provide greater antibacterial protection against SM and LB.

Comparison of fiber reinforcing methods of composite resin: A flexural strength and stereo microscopy study.

This study aimed to compare the effect of fiber reinforcing methods on the flexural strength and failure modes of indirect composite resins. Based on the reinforcement methods, the bar specimens (3 × 3 × 25 mm) were divided into five groups (n = 20). Glass or polyethylene fibers were used for reinforcement of indirect composite resins. Fibers were either light polymerized and mixed with indirect composite resin or mixed with indirect composite resin after resin application and polymerized together. Indirect composite resin without fiber reinforcement was used as control. All five types of specimens were stored in distilled water at 37°C for 24 h. Half of the specimens were additionally thermocycled. Then the specimens were tested in a three-point bending test. Failure types were examined and categorized by using stereo microscope. The data were analyzed using two-way ANOVA and Tukey HSD test. Flexural strength was found to be significantly higher for fiber-reinforced indirect resin composites than control. However, the fiber-reinforced groups did not present any significant difference. Analysis revealed aging does not affect the flexure strength of fiber reinforcement of indirect composite resin. The study concluded that the flexure strength of indirect composite resins was improved with fiber reinforcement. Different fiber reinforcement methods demonstrated similar effects on the flexure strength of indirect composite resin. Reinforcement with glass or polyethylene fibers presented the potential to improve the mechanical properties of indirect composite resins. RESEARCH HIGHLIGHTS: Flexural strength of indirect composite resins are affected by the reinforcement of composites with glass or polyethylene fibers. Aging with thermocycling has no effect on the flexural strength of the indirect composite resins, however can cause catastrophic failures in material.

Gender difference in prevalence of signs and symptoms of temporomandibular joint disorders: a retrospective study on 243 consecutive patients.

BACKGROUND: This study evaluated the prevalence of the signs and symptoms of temporomandibular joint disorder (TMD) among patients with TMD symptoms. METHODS: Between September 2011 and December 2011, 243 consecutive patients (171 females, 72 males, mean age 41 years) who were referred to the Department of Prosthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon were examined physically and completed a questionnaire regarding age, gender, social status, general health, antidepressant drug usage, dental status, limited mouth opening, temporomandibular joint (TMJ) sounds, and parafunctions (bruxism, clenching). The data were analyzed using the chi-square test and binary logistic regression model (alpha = 0.05). RESULTS: With a frequency of 92%, pain in the temporal muscle was the most common symptom, followed by pain during mouth opening (89%) in both genders. TMJ pain at rest, pain in the masseter muscle, clicking, grinding, and anti-depressant use were significantly more frequent in females than males. Age (p=0.006; odds ratio 0.954; 95% CI 0.922-0.987) and missing teeth (p=0.003; odds ratio 3.753; 95% CI 1.589-8.863) had significant effects on the prevalence of TMD. CONCLUSION: Females had TMD signs and symptoms more frequently than males in the study population. The most common problem in both genders was pain.

A 3-year follow-up of the rehabilitation of Papillon-Lefèvre syndrome by dental implants.

PURPOSE: Papillon-Lefèvre syndrome is a rare autosomal recessive genetic disorder characterized by palmar-plantar hyperkeratosis, with rapidly progressive periodontitis and premature loss of both deciduous and permanent teeth. This article presents the prosthetic rehabilitation of a patient with Papillon-Lefèvre syndrome with dental implants. MATERIALS AND METHODS: Twelve titanium implants were installed in the mandible and maxilla in an 18-year-old male patient with Papillon-Lefèvre syndrome. RESULTS: At 3 years follow-up, all implants were clinically stable and no pain or infection was found. The patient continues to be seen at regular follow-up visits. CONCLUSION: Twelve-implant installation in Papillon-Lefèvre syndrome with 3 years' follow-up has not claimed before. We not only successfully treated our patient functionally and esthetically with dental implant rehabilitation, but also provided psychological benefits to the patient.

Bonding effectiveness of a self-adhesive resin-based luting cement to dentin after provisional cement contamination.

PURPOSE: To evaluate the influence of provisional luting cements on the bonding performance of a resin-based self-adhesive luting cement to dentin vs that of currently used resin-based luting agents with different adhesion strategies. MATERIALS AND METHODS: Forty-five prepared human molars were randomly and equally divided into three main groups according to the type of provisional luting cement applied: eugenol-containing provisional cement (Temp Bond, Kerr), eugenol-free provisional cement (Temp Bond NE, Kerr), and control where the provisionalization step was omitted. Each group was further subdivided into 3 groups based on the category of adhesive systems/ luting materials used: a two-step etch-and-rinse system (Single Bond/RelyX ARC; 3M ESPE) (RX), a two-step self-etching system (Clearfil Liner Bond 2V/ Panavia F; Kuraray) (PF), and a self-adhesive luting cement (Rely X Unicem; 3M ESPE) (RU). Finally, 9 groups of 5 teeth each were prepared for the microtensile test. RESULTS: Two-way analysis of variance (ANOVA) and post-hoc Bonferroni tests revealed that definitive luting cement, provisional luting cement, and the interactions of these two factors had significant influences on dentin bond strength. The highest bond strength was obtained for PF (32.05 MPa), followed by RX (26.57 MPa) and RU (16.56 MPa) for the controls. Contamination with either eugenol-containing or eugenol-free provisional cement significantly decreased the bonding effectiveness of RX (19.08 and 19.69 MPa, respectively) and PF (14.21 and 16.67 MPa respectively) to dentin (p < 0.05). RU showed comparable bond strength values before and after provisional cement (13.93 and 14.49 MPa, respectively) application (p > 0.05). Eugenol in provisional luting cement did not produce material-related alterations in the bonding performance of the resin luting cements tested (p > 0.05). CONCLUSION: Based on these results, the self-adhesive cement which was not influenced by the provisional cement application may be promising. However, long-term laboratory and clinical performance of this cement needs to be assessed before recommending it as an alternative to the technically more demanding approaches. Moreover, an effective surface cleansing procedure is critical to achieve a successful bond between the contaminated dentin and luting cement.

Complicated subgingivally fractured central and lateral incisors: case report.

Dental trauma sometimes causes fractures in the maxillary anterior teeth leading to esthetic, functional and phonetic problems. In this report, we describe the treatment of central and lateral incisors simultaneously subgingivally fractured due to dental trauma. Treatment involved flap surgery, reattachment and splinting of the fractured fragments with glass-fibre and composite resin. This reattachment technique, which uses advanced adhesive systems, is an option that offers satisfactory esthetic and functional outcomes.

Could digital imaging be an alternative for digital colorimeters?

This study evaluated the colour parameters of composite and ceramic shade guides determined using a colorimeter and digital imaging method with illuminants at different colour temperatures. Two different resin composite shade guides, namely Charisma (Heraeus Kulzer) and Premise (Kerr Corporation), and two different ceramic shade guides, Vita Lumin Vacuum (VITA Zahnfabrik) and Noritake (Noritake Co.), were evaluated at three different colour temperatures (2,700 K, 2,700-6,500 K, and 6500 K) of illuminants. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2 and C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc.). The data were analysed using two-way ANOVA, and Pearson's correlation. While mean L* values of both composite and ceramic shade guides were not affected from the colour temperature, L* values obtained with the colorimeter showed significantly lower values than those of the digital imaging (p < 0.01). At combined 2,700-6500 K colour temperature, the means of a* values obtained from colorimeter and digital imaging did not show significant differences (p > 0.05). For both composite and ceramic shade guides, L* and b* values obtained from colorimeter and digital imaging method presented a high level of correlation. High-level correlations were also acquired for a* values in all shade guides except for the Charisma composite shade guide. Digital imaging method could be an alternative for the colorimeters unless the proper object-camera distance, digital camera settings and suitable illumination conditions could be supplied. However, variations in shade guides, especially for composites, may affect the correlation.

Assessment of color parameters of composite resin shade guides using digital imaging versus colorimeter.

PURPOSE: This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. MATERIALS AND METHODS: Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. RESULTS: Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p < 0.001) but there was no significant difference with the digital imaging method (p = 0.099). With both measurement methods in total, 80% of the shade guide pairs from different composites (97/120) showed color differences greater than 3.7 (moderately perceptible mismatch), and 49% (59/120) had obvious mismatch (ΔE > 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. CONCLUSION: The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection.

Rehabilitation of an extracted anterior tooth space using fiber-reinforced composite and the natural tooth.

Conservative solutions for the restoration of a single edentulous space in the anterior maxilla present an esthetic challenge to the clinician. A 45-year-old male patient whose right upper central tooth was planned to be extracted was referred to our clinic for a conservative, rapid, and economic treatment. After radiographic and clinical examinations, it was decided that the tooth which was to be extracted should be used for the restoration of its own extracted area. The extracted tooth was splinted to adjacent teeth with the aid of the grooves and fiber-reinforced composite (everStick, StickTech Ltd., Turku, Finland). Following an early and unexpected failure of the restoration, the fiber layer was thickened twice with a flowable composite resin (Stick Flow, Stick Tech Ltd.) which fit better to the grooves. The restoration satisfied the patient with a good mechanical behavior, esthetics, and long-term durability after 12 months while. Restoring the missing tooth area with the patient's own tooth is advantageous when combined with modern adhesive techniques. The clinician must pay attention to the mechanical adaptation of the restoration and the technique sensitivity of the applied adhesive system.

Loss of surface enamel after bracket debonding: an in-vivo and ex-vivo evaluation.

INTRODUCTION: The objective of this study was to evaluate the surface enamel after bracket debonding and residual resin removal. METHODS: Thirty patients (female, 20; male, 10; mean age, 18.4 years) who completed orthodontic treatment with fixed appliances (Twin Brackets, 3M Unitek, Monrovia, Calif) (n = 525) were included. The amounts of adhesive left on the tooth surfaces and the bracket bases were evaluated with the adhesive remnant index (ARI). ARI(tooth) (n = 498) was assessed on digital photographs by 2 operators. After resin removal and polishing, epoxy replicas were made from the maxillary anterior teeth (n = 62), and enamel surfaces were scored again with the enamel surface index. Elemental analysis was performed on the debonded bracket bases by using energy dispersive x-ray spectrometry mean area scanning analysis. The percentages of calcium and silicon were summed up to 100%. Tooth damage was estimated based on the incidence of calcium from enamel in relation to silicon from adhesive (Ca%) and the correlation between the ARI(bracket) and Ca%. RESULTS AND CONCLUSIONS: While ARI(tooth) results showed score 3 as the most frequent (41%) (P<0.05), followed by scores 0, 1, and 2 (28.7%, 17.9%, and 12.4%, respectively), ARI(bracket) results showed score 0 more often (40.6%) than the other scores (P<0.05). Maxillary anterior teeth had significantly more scores of 3 (49%) than the other groups of teeth (10%-25%) (chi-square; P<0.001). There were no enamel surface index scores of 0, 3, or 4. No correlation between the enamel surface index and ARI(tooth) scores was found (Spearman rho = 0.014, P = 0.91). The incidence of Ca% from the scanned brackets showed significant differences between the maxillary and mandibular teeth (14% ± 8.7% and 11.2% ± 6.5%, respectively; P <0.05), especially for the canines and second premolars (Kruskal-Wallis test, P<0.01). With more remnants on the bracket base, the Ca% was higher (Jonckheere Terpstra test, P<0.05). Iatrogenic damage to the enamel surface after bracket debonding was inevitable. Whether elemental loss from enamel has clinical significance is yet to be determined in a long-term clinical follow-up of the studied patient population.