Assessing color mismatch in single-shade composite resins for enamel replacement.

STATEMENT OF PROBLEM: Shade selection is a challenge in restorative dentistry. While single-shade composite resins may simplify this process, whether the color mismatch between this composite resin and the substrate is within acceptable levels to ensure successful outcomes is unclear. PURPOSE: The purpose of this in vitro study was to assess the influence of background and surrounding shade, thickness, and proximity to the surrounding on color mismatch when shaded and single-shade composite resins are used in the center of an enamel layer. MATERIAL AND METHODS: Two-layer specimens mimicking dentin (the background) and enamel (the surrounding and center) were prepared. Two shades were used for the background and the surrounding layer (OA1/A1 and OA3/A3). At the Ø3-mm center, 2 single-shade composite resins were placed, Omnichroma (OM) and Admira Fusion x-tra (FU), and also shaded composite resins A1, WE, A3, and C2. For the OA1/A1 background and surrounding, shades A1 and WE served as positive controls, while the A3 and C2 were negative controls. For OA3/A3, these controls were reversed. Two enamel layer thicknesses were evaluated (0.5- and 1.0-mm). Reflectance measurements were made at 0.0, 1.0, 2.0, and 2.5 mm from the center. Color differences were calculated between those at 2.5 mm and at other distances (ΔE0, ΔE1, and ΔE2). Data analysis employed a 4-way repeated measure ANOVA with Bonferroni corrections for the pair-wise comparisons (α=.05). RESULTS: Background and surrounding shade, central shade, distance, and thickness affected color mismatch (P<.05). For the OA1/A1 specimens, single-shade color mismatch values were found between both the positive and negative controls (P<.05). For the OA3/A3 specimens, the color mismatch did not differ significantly from that of negative controls (P>.05). No difference was found between ΔE0 and ΔE1, but each was distinct from ΔE2. Thickness did not affect the color mismatch of the single-shade composite resins (P<.05). CONCLUSIONS: Single-shade composite resins for enamel replacement showed higher color mismatches compared with positive controls.

Reliability of the color measurement of resin composites using images obtained using a stereoscopic loupe.

This study assessed the reliability of a color measurement method using images obtained from a charge-coupled device (CCD) camera and a stereoscopic loupe. Disc-shaped specimens were created using the composite Filtek Z350 XT (shades DA1, DA2, DA3, and DA4) (n = 3). CIELAB color coordinates of the specimens were measured using the spectrophotometer SP60 over white and black backgrounds. Images of the same specimens were taken using a CCD camera attached to a stereoscopic loupe. The color of the image was measured (red-green-blue [RGB]) using an image processing software and converted to CIELAB coordinates. For each color coordinate, data from images were adjusted using linear regressions predicting those values from SP60. The whiteness index for dentistry (WID) and translucency parameter (TP00) of the specimens as well as the color differences (ΔE00) among pairwise shades were calculated. Data were analyzed via repeated-measures analysis of variance and Tukey's post hoc test (α = 0.05). Images obtained using the loupe tended to be darker and redder than the actual color. Data adjustment resulted in similar WID, ΔE00, and TP00 values to those observed for the spectrophotometer. Differences were observed only for the WID of shade DA3 and ΔE00 for comparing DA1 and DA3 over the black background. However, these differences were not clinically relevant. The use of adjusted data from images taken using a stereoscopic loupe is considered a feasible method for color measurement.

Reliability of the color measurement of resin composites using images obtained using a stereoscopic loupe

Abstract This study assessed the reliability of a color measurement method using images obtained from a charge-coupled device (CCD) camera and a stereoscopic loupe. Disc-shaped specimens were created using the composite Filtek Z350 XT (shades DA1, DA2, DA3, and DA4) (n = 3). CIELAB color coordinates of the specimens were measured using the spectrophotometer SP60 over white and black backgrounds. Images of the same specimens were taken using a CCD camera attached to a stereoscopic loupe. The color of the image was measured (red-green-blue [RGB]) using an image processing software and converted to CIELAB coordinates. For each color coordinate, data from images were adjusted using linear regressions predicting those values from SP60. The whiteness index for dentistry (WID) and translucency parameter (TP00) of the specimens as well as the color differences (ΔE00) among pairwise shades were calculated. Data were analyzed via repeated-measures analysis of variance and Tukey's post hoc test (α = 0.05). Images obtained using the loupe tended to be darker and redder than the actual color. Data adjustment resulted in similar WID, ΔE00, and TP00 values to those observed for the spectrophotometer. Differences were observed only for the WID of shade DA3 and ΔE00 for comparing DA1 and DA3 over the black background. However, these differences were not clinically relevant. The use of adjusted data from images taken using a stereoscopic loupe is considered a feasible method for color measurement.

Prevalence of lectures about dental esthetics and female speakers in three Brazilian conferences.

This study analyzed the prevalence of lectures involving esthetics in the scientific program of Brazilian dental conferences and the gender distribution of speakers. All lectures presented in three dental conferences (Bahia, São Paulo, and Goiás states) held from 2016 to 2020 were evaluated. Three investigators individually divided the lectures according to the specialties recognized by the Brazilian Federal Council of Dentistry (FCD) based on their titles. The lectures were also classified as involving or not esthetics, and the speaker`s gender was recorded. Descriptive statistical analyses were performed, and Chi-square tests assessed possible associations between factors. The words most cited in the titles of the lectures were "esthetic" (13.6%), "dentistry" (9.9%), and "treatment" (8.1%). Oral diseases were barely mentioned in the titles (up to 1.3%). The highest number of lectures was observed for the specialty of Restorative Dentistry (22.3%), followed by Prosthodontics (18.5%). Approximately one-third of lectures involved some aesthetic aspect, but this percentage ranged from 71.9 to 78.6% for the two specialties with more lectures. Regarding the speaker`s gender, the inequity was higher for lectures involving esthetics (81.6% of males) than for topics unrelated to esthetics (66.7%). More male speakers than females were observed for all specialties. The highest gender gap was observed for Pediatric Dentistry with 62.4% male speakers, although only 10.6% of FCD registered specialists were men. In conclusion, the Brazilian dental conferences analyzed seemed to favor offering lectures dealing with esthetic topics and male speakers.

The role of interface distance and underlying substrate on the color adjustment potential of single-shade composites.

OBJECTIVE: This study assessed how the distance from the composite interface and the underlying chromatic substrate affect the color adjustment potential (CAP) of two single-shade composites. MATERIALS AND METHODS: Cylinder-shaped specimens were created using Vittra APS Unique (VU), Charisma Diamond One (DO), and a shaded (A3) composite. Some single-shade specimens were surrounded by the A3 composite, forming dual specimens. Color measurements of simple specimens were taken against a gray background using a spectrophotometer. All specimens were positioned at a 45° angle in a viewing booth under illuminant D65, and images were captured with a DSLR camera against gray or A3 backgrounds. Image colors were measured using image processing software and converted to CIELAB coordinates. Color differences (ΔE00 ) between the single-shade composites and the A3 composite were calculated. CAP was determined by comparing data from simple and dual specimens. RESULTS: No clinically significant differences were observed between color measurements obtained from images and the spectrophotometer. CAP was higher for DO compared to VU and increased as the distance from the composite interface decreased and when specimens were positioned against an A3 background. CONCLUSION: The color adjustment potential increased with decreased distance from the composite interface and against a chromatic background. CLINICAL SIGNIFICANCE: Achieving satisfactory color match in restorations using single-shade composites is crucial, and selecting an appropriate underlying substrate is essential. The color adjustment gradually decreases from the restoration margins towards its center.

Prevalence of lectures about dental esthetics and female speakers in three Brazilian conferences

Abstract This study analyzed the prevalence of lectures involving esthetics in the scientific program of Brazilian dental conferences and the gender distribution of speakers. All lectures presented in three dental conferences (Bahia, São Paulo, and Goiás states) held from 2016 to 2020 were evaluated. Three investigators individually divided the lectures according to the specialties recognized by the Brazilian Federal Council of Dentistry (FCD) based on their titles. The lectures were also classified as involving or not esthetics, and the speaker`s gender was recorded. Descriptive statistical analyses were performed, and Chi-square tests assessed possible associations between factors. The words most cited in the titles of the lectures were "esthetic" (13.6%), "dentistry" (9.9%), and "treatment" (8.1%). Oral diseases were barely mentioned in the titles (up to 1.3%). The highest number of lectures was observed for the specialty of Restorative Dentistry (22.3%), followed by Prosthodontics (18.5%). Approximately one-third of lectures involved some aesthetic aspect, but this percentage ranged from 71.9 to 78.6% for the two specialties with more lectures. Regarding the speaker`s gender, the inequity was higher for lectures involving esthetics (81.6% of males) than for topics unrelated to esthetics (66.7%). More male speakers than females were observed for all specialties. The highest gender gap was observed for Pediatric Dentistry with 62.4% male speakers, although only 10.6% of FCD registered specialists were men. In conclusion, the Brazilian dental conferences analyzed seemed to favor offering lectures dealing with esthetic topics and male speakers.

Resumo Este estudo analisou a prevalência de palestras envolvendo estética na programação científica de congressos de Odontologia brasileiros, e a distribuição do gênero dos palestrantes. Todas as palestras apresentadas em três congressos de Odontologia (CIOBA, CIOGO, and CIOSP) entre 2016 e 2020 foram avaliadas. Três avaliadores utilizaram os títulos das palestras para dividi-las entre as especialidades reconhecidas pelo Conselho Federal de Odontologia (CFO) do Brasil. As palestras foram também classificadas como envolvendo ou não estética, e o gênero do palestrante foi registrado. Análises estatísticas descritivas foram realizadas, e testes de Qui-quadrado avaliaram possíveis interações entre fatores. A palavra mais citada nos títulos das palestras foi "estética" (13,6%), seguido por "odontologia" (9,9%) e "tratamento" (8,1%). Doenças orais foram raramente mencionadas nos títulos (até 1,3%). O maior número de palestras foi observado para a especialidade de Dentística (22,3%), seguido por Prótese Dental (18,3%). Aproximadamente um terço das palestras envolviam algum aspecto estético, com porcentagens entre 71,9 a 78,6% para as duas especialidades com mais palestras. Em relação ao gênero do palestrante, a inequidade foi maior para palestras envolvendo estética (81,6% de homens) que para tópicos não relacionadas à estética (66,7%). Mais palestrantes do sexo masculino que feminino foram observados para todas as especialidades. A maior discrepância entre os gêneros foi observada para Odontopediatria, uma especialidade com 62,4% dos palestrantes do sexo masculino, embora apenas 10,6% dos especialistas registrados no CFO eram homens. Como conclusão, os congressos de Odontologia Brasileiros parecem preferir palestras abordando tópicos de estética e palestrantes do sexo masculino.

Background and surrounding colors affect the color blending of a single-shade composite.

This study evaluated the background and effect of surrounding colors on the color blending of a single-shade composite used in a thin layer. Disc-shaped specimens (1.0 mm thickness) were built with the Vittra APS Unique composite surrounded (dual specimens) or not surrounded (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built with only control composites. The specimen color was measured against white and black backgrounds with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WID) was calculated for simple specimens. Differences (ΔE00) in color and translucency parameters (ΔTP00) between the simple/dual specimens and the controls were calculated. The translucency adjustment potential (TAP) and color adjustment potential (CAP) were estimated based on the ratios between data from simple and dual specimens. The Vittra APS Unique composite showed higher WID values than the controls. No differences between ΔTP00_SIMPLE and ΔTP00_DUAL were observed for any of the shades. The composite shade did not affect TAP values. The lowest values of ΔE00_SIMPLE and ΔE00_DUAL were observed for shade A1 regardless of the background color. For the white background, ΔE00_SIMPLE values did not differ from those of ΔE00_DUAL for all shades. Only A1 showed ΔE00_DUAL values lower than ΔE00_SIMPLE when the black background was used. The highest modulus of CAP (negative values for the white background) was observed when shade A1 surrounded the Vittra APS Unique composite. The color blending ability of the single-shade resin composite used in a thin layer was affected by both the surrounding shade and background color.

Effects of surrounding and underlying shades on the color adjustment potential of a single-shade composite used in a thin layer.

Objectives: This study aimed to evaluate the surrounding and underlying shades' effect on the color adjustment potential (CAP) of a single-shade composite used in a thin layer. Materials and Methods: Cylinder specimens (1.0 mm thick) were built with the Vittra APS Unique composite, surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built only with the control composites. Each specimen's color was measured against white and black backgrounds or the simple control specimens with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WID) and translucency parameters (TP00) were calculated for simple specimens. Differences (ΔE00) in color between the simple/dual specimens and the controls were calculated. The CAP was calculated based on the ratios between data from simple and dual specimens. Results: The Vittra APS Unique composite showed higher WID and TP00 values than the controls. The highest values of ΔE00 were observed among simple specimens. The color measurements of Vittra APS Unique (simple or dual) against the control specimens presented the lowest color differences. Only surrounding the single-shade composite with a shaded composite barely impacted the ΔE00. The highest CAP values were obtained using a shaded composite under simple or dual specimens. Conclusions: The CAP of Vittra APS Unique was strongly affected by the underlying shade, while surrounding this composite with a shaded one barely affected its color adjustment.

Background and surrounding colors affect the color blending of a single-shade composite

Abstract This study evaluated the background and effect of surrounding colors on the color blending of a single-shade composite used in a thin layer. Disc-shaped specimens (1.0 mm thickness) were built with the Vittra APS Unique composite surrounded (dual specimens) or not surrounded (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built with only control composites. The specimen color was measured against white and black backgrounds with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WID) was calculated for simple specimens. Differences (ΔE00) in color and translucency parameters (ΔTP00) between the simple/dual specimens and the controls were calculated. The translucency adjustment potential (TAP) and color adjustment potential (CAP) were estimated based on the ratios between data from simple and dual specimens. The Vittra APS Unique composite showed higher WID values than the controls. No differences between ΔTP00_SIMPLE and ΔTP00_DUAL were observed for any of the shades. The composite shade did not affect TAP values. The lowest values of ΔE00_SIMPLE and ΔE00_DUAL were observed for shade A1 regardless of the background color. For the white background, ΔE00_SIMPLE values did not differ from those of ΔE00_DUAL for all shades. Only A1 showed ΔE00_DUAL values lower than ΔE00_SIMPLE when the black background was used. The highest modulus of CAP (negative values for the white background) was observed when shade A1 surrounded the Vittra APS Unique composite. The color blending ability of the single-shade resin composite used in a thin layer was affected by both the surrounding shade and background color.

Effect of surrounded shade and specimen`s thickness on color adjustment potential of a single-shade composite.

This study evaluated the effect of surrounded shade and specimens` thickness on the color adjustment potential (CAP) of a single-shade composite. The composite Vittra APS Unique was surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens of the control composite were also confectioned. Opacity and whiteness index for dentistry (WID) were calculated for simple specimens. Color differences between the simple (ΔE*SIMPLE)/ dual specimens (ΔE*DUAL) and the controls were calculated. CAP was calculated based on the ratio between ΔE* SIMPLE and ΔE* DUAL. The tested composite presented lower opacity (53 to 62% vs. 80 to 93%) and higher WID (≈ 42 vs. 18 to 32) than controls. Irrespective of the specimens' thickness (1.0/ 1.5 mm), the lowest values of ΔE* SIMPLE (11.1/ 10.8) and ΔE*DUAL (7.2/ 6.1) were observed using the surrounding shade A1. The shade A3 yielded higher ΔE*SIMPLE (16.4/ 17.1) and ΔE* DUAL (11.3/ 12.3) than the A2 (ΔE*SIMPLE = 13.4/ 14.6; and ΔE* DUAL = 9.7/ 10.3). The specimen`s thickness significantly affected the CAP (0.35 and 0.44 for 1.0 and 1.5 mm, respectively) only for shade A1, which had the highest CAP values. The shade A3 resulted in higher CAP values (0.31) than A2 (0.27) when 1.0-mm thick specimens were used, but similar values were observed for 1.5 thick specimens (≈ 0.29). In conclusion, both surrounding shade and specimen thickness can affect the CAP of a single-shade resin composite.

Effect of surrounded shade and specimen`s thickness on color adjustment potential of a single-shade composite

Abstract This study evaluated the effect of surrounded shade and specimens` thickness on the color adjustment potential (CAP) of a single-shade composite. The composite Vittra APS Unique was surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens of the control composite were also confectioned. Opacity and whiteness index for dentistry (WID) were calculated for simple specimens. Color differences between the simple (ΔE*SIMPLE)/ dual specimens (ΔE*DUAL) and the controls were calculated. CAP was calculated based on the ratio between ΔE* SIMPLE and ΔE* DUAL. The tested composite presented lower opacity (53 to 62% vs. 80 to 93%) and higher WID (≈ 42 vs. 18 to 32) than controls. Irrespective of the specimens' thickness (1.0/ 1.5 mm), the lowest values of ΔE* SIMPLE (11.1/ 10.8) and ΔE*DUAL (7.2/ 6.1) were observed using the surrounding shade A1. The shade A3 yielded higher ΔE*SIMPLE (16.4/ 17.1) and ΔE* DUAL (11.3/ 12.3) than the A2 (ΔE*SIMPLE = 13.4/ 14.6; and ΔE* DUAL = 9.7/ 10.3). The specimen`s thickness significantly affected the CAP (0.35 and 0.44 for 1.0 and 1.5 mm, respectively) only for shade A1, which had the highest CAP values. The shade A3 resulted in higher CAP values (0.31) than A2 (0.27) when 1.0-mm thick specimens were used, but similar values were observed for 1.5 thick specimens (≈ 0.29). In conclusion, both surrounding shade and specimen thickness can affect the CAP of a single-shade resin composite.

Resumo Este estudo avaliou o efeito da cor circundante e da espessura da amostra no potencial de ajuste de cor (PAC) de uma resina monocromática. O compósito Vittra APS Unique foi circundado (amostras duplas) ou não (amostras simples) com um compósito controle (cor A1, A2 ou A3). Amostras simples do compósito controle também foram confeccionadas. A opacidade e o índice de brancura para odontologia (IBO) foram calculados para as amostras simples. As diferenças de cor entre amostras simples (ΔE*SIMPLE) / duplas (ΔE*DUAL) e os controles foram calculados. PAC foi calculado baseado na razão entre ΔE* SIMPLE e ΔE* DUAL. O compósito testado apresentou menor opacidade (53 a 62% vs. 80 a 93%) e maior IBO (≈ 42 vs. 18 a 32) que os controles. Independente da espessura da amostra (1,0/ 1,5 mm), os valores mais baixos de ΔE* SIMPLE (11,1/ 10,8) e ΔE*DUAL (7,2/ 6,1) foram observadas quando a resina circundante era A1. A cor A3 resultou em maior ΔE*SIMPLE (16,4/ 17,1) e ΔE* DUAL (11,3/ 12,3) do que A2 (ΔE*SIMPLE = 13,4/ 14,6; e ΔE* DUAL = 9,7/ 10,3). A espessura das amostras afetou significativamente o PAC (0,35 e 0,44 para 1,0 e 1,5 mm, respectivamente) apenas para a cor A1, que teve os maiores valores de PAC. A cor A3 resultou nos maiores valores de PAC (0,31) que A2 (0,27) quando amostras de 1,0 mm de espessura foram usadas, mas valores similares foram observados para amostras de 1,5 mm (≈ 0,29). Como conclusão, tanto a cor circundante como a espessura das amostras podem afetar o PAC de um compósito resinoso monocromático.

The effectiveness of the supplementary use of the XP-endo Finisher on bacteria content reduction: a systematic review and meta-analysis.

OBJECTIVES: This systematic review evaluated the efficacy of the supplementary use of the XP-endo Finisher on bacteria content reduction in the root canal system. MATERIALS AND METHODS: In-vitro studies evaluating the use of the XP-endo Finisher on bacteria content were searched in four databases in July 2020. Two authors independently screened the studies for eligibility. Data were extracted, and risk of bias was assessed. Data were meta-analyzed by using random-effects model to compare the effect of the supplementary use (experimental) or not (control) of the XP-endo Finisher on bacteria counting reduction, and results from different endodontic protocols were combined. Four studies met the inclusion criteria while 1 study was excluded from the meta-analysis due to its high risk of bias and outlier data. The 3 studies that made it to the meta-analysis had an unclear risk of bias for at least one criterion. RESULTS: No heterogeneity was observed among the results of the studies included in the meta-analysis. The study excluded from the meta-analysis assessing the bacteria counting deep in the dentin demonstrated further bacteria reduction upon the use of the XP-endo Finisher. CONCLUSIONS: This systematic review found no evidence supporting the supplementary use of the XP-endo Finisher on further bacteria counting the reduction in the root canal.

Color assessment of resin composite by using cellphone images compared with a spectrophotometer.

OBJECTIVES: This study assessed the reliability of digital color measurements using images of resin composite specimens captured with a cellphone. MATERIALS AND METHODS: The reference color of cylindrical specimens built-up with the use of resin composite (shades A1, A2, A3, and A4) was measured with a portable spectrophotometer (CIELab). Images of the specimens were obtained individually or pairwise (compared shades in the same photograph) under standardized parameters. The color of the specimens was measured in the images using RGB system and converted to CIELab system using image processing software. Whiteness index (WID) and color differences (ΔE00) were calculated for each color measurement method. For the cellphone, the ΔE00 was calculated between the pairs of shades in separate images and in the same image. Data were analyzed using 2-way repeated-measures analysis of variance (α = 0.05). Linear regression models were used to predict the reference ΔE00 values of those calculated using color measured in the images. RESULTS: Images captured with the cellphone resulted in different WID values from the spectrophotometer only for shades A3 and A4. No difference to the reference ΔE00 was observed when individual images were used. In general, a similar ranking of ΔE00 among resin composite shades was observed for all methods. Stronger correlation coefficients with the reference ΔE00 were observed using individual than pairwise images. CONCLUSIONS: This study showed that the use of cellphone images to measure the color difference seems to be a feasible alternative providing outcomes similar to those obtained with the spectrophotometer.

Role of enamel and dentin on color changes after internal bleaching associated or not with external bleaching

Abstract Objective To evaluate the effect of the association between external and internal tooth bleaching on color changes in dentin and enamel, individually or recombined, previously stained with triple antibiotic paste (TAP). Methodology Forty enamel-dentin specimens from bovine incisors were separated into ten blocks according to similarity in their whiteness index (WID). Three specimens within each block were stained by dentin exposure to TAP, and the remaining specimen was used as control to estimate color changes. Specimens were sectioned to separate tissues, and dentin and enamel colors were measured individually and after being recombined. Alterations in color (CIEDE2000 - ΔE00) and translucency parameter (TP) resulting from staining were estimated by color difference between stained and control specimens. The contribution of each tissue to the color change (CTCC) was also calculated. Non-sectioned stained specimens were bleached by applying sodium perborate on dentin, associated or not with 35% hydrogen peroxide on enamel. Color changes caused by bleaching procedures were estimated and data were analyzed using the paired t-test or Two-way repeated measures ANOVA. Results TAP caused more pronounced changes in dentin, but enamel color was also affected. Both protocols presented a similar ΔE00, and dentin showed the greater color change. After exposure to TAP, we observed a reduction in WID; WID values were the same for bleached and control specimens regardless of protocol. We found no significant effect of substrate and bleaching technique on TP. Enamel played a more critical role in color changes caused by either staining or bleaching procedures. Conclusion Enamel color played a greater role on tooth color changes than dentin. External and internal bleaching association did not improve bleaching effect on specimens stained with TAP.

Role of enamel and dentin on color changes after internal bleaching associated or not with external bleaching.

OBJECTIVE: To evaluate the effect of the association between external and internal tooth bleaching on color changes in dentin and enamel, individually or recombined, previously stained with triple antibiotic paste (TAP). METHODOLOGY: Forty enamel-dentin specimens from bovine incisors were separated into ten blocks according to similarity in their whiteness index (WID). Three specimens within each block were stained by dentin exposure to TAP, and the remaining specimen was used as control to estimate color changes. Specimens were sectioned to separate tissues, and dentin and enamel colors were measured individually and after being recombined. Alterations in color (CIEDE2000 - ΔE00) and translucency parameter (TP) resulting from staining were estimated by color difference between stained and control specimens. The contribution of each tissue to the color change (CTCC) was also calculated. Non-sectioned stained specimens were bleached by applying sodium perborate on dentin, associated or not with 35% hydrogen peroxide on enamel. Color changes caused by bleaching procedures were estimated and data were analyzed using the paired t-test or Two-way repeated measures ANOVA. RESULTS: TAP caused more pronounced changes in dentin, but enamel color was also affected. Both protocols presented a similar ΔE00, and dentin showed the greater color change. After exposure to TAP, we observed a reduction in WID; WID values were the same for bleached and control specimens regardless of protocol. We found no significant effect of substrate and bleaching technique on TP. Enamel played a more critical role in color changes caused by either staining or bleaching procedures. CONCLUSION: Enamel color played a greater role on tooth color changes than dentin. External and internal bleaching association did not improve bleaching effect on specimens stained with TAP.

Ultra-low frequency transcutaneous electric nerve stimulation does not affect the centric relation registration.

OBJECTIVE: To evaluate the influence of ULF-TENS on the displacement of the mandibular condyle and on the repeatability of centric relation (CR) registration of three different techniques: bimanual manipulation (BM), long strip technique, and harmonic centric occlusal relationship (R.O.C.A. wires). METHODS: Twenty-five participants without temporomandibular disorder (TMD) underwent two study stages conducted via electronic position analysis: (1) three CR records were made, one for each manipulation technique; (2) the ULF-TENS was applied for 30 min, and after that the same CR records were repeated. STATISTICAL ANALYSES: Mann-Whitney, ICC, and one-tailed F test. RESULTS: The ULF-TENS did not influence the condyle total displacement, regardless of CR recording technique used (p > 0.05). BM showed an improvement in repeatability after ULF-TENS. DISCUSSION: Concerning the variance, BM showed less variation at the X-axis. Long strip technique and R.O.C.A. wires varied less at the Y-axis. Long strip technique was again less variable at the Z-axis.

Comparison of mandibular movements in TMD by means of a 3D ultrasonic system and digital caliper rule.

OBJECTIVE: To compare the amplitude of mandibular movement measurements obtained by two different methods: the ultrasound JAM system and digital caliper rule in individuals with temporomandibular disorder (TMD) vs. METHOD: Sixty individuals, without distinction between sex and age were evaluated: 30 with diagnosis of TMD (RDC/TMD) and 30 controls. Mandibular movements of opening, protrusion, and left and right laterality were measured by means of two Instruments: Digital caliper rule and 3D ultrasonic Jaw Motion Analyzer (JMA-Zebris Medizintechnik, Isny/Allgäu, Germany). Data obtained were analyzed by descriptive analysis and compared by parametric statistics (Student's t-test), adopting a 5% level of significance. RESULTS: When comparing the digital caliper rule with JMA, no significant differences were found for any of the movements evaluated (p > 0.05). In the comparison between groups, a difference was found in protrusion for both instruments used: JMA (p = 0.004) and digital caliper rule (p = 0.003), with the TMD group presenting reduced movement of protrusion when compared with the control group. DISCUSSION: This study found no differences in obtaining the amplitude of mandibular movements when using the digital caliper rule or JMA system; both methods are effective. However, the ultrasonic system allows other types of analyses to be performed, such as the trajectory and speed of movement. Among the mandibular movements analyzed, protrusion was shown to be more compromised and limited in TMDs.

An evaluation of patients' knowledge about perioperative information for third molar removal.

PURPOSE: Third molar removal is usually accompanied by a high degree of patient anxiety. Lack of knowledge about the procedure is a major contributor to this anxiety. The aim of this study was to investigate the perioperative perceptions of patients who underwent extraction of third molars to assess their concerns during the surgical experience. MATERIALS AND METHODS: Issues related to preoperative, intraoperative, and postoperative phases of the experience were assessed with the purpose of identifying the most frequent questions and misconceptions. Data were assessed to correlate the influence of previous experience with extraction(s) with the appropriate knowledge of third molar surgery, as well as knowledge variations as to the age and gender of the patients. RESULTS: The sample was composed of 67 patients (43 female patients and 24 male patients) divided into 2 groups: The first had some previous experience with extractions (25 patients), and the second had no experience (42 patients). The most frequent questions regarded the number of teeth to be extracted (65.4%), and the most prevalent misconception was about medications before surgery (28.4%). Patients with a previous history of dental extractions had more questions about use of medication before surgery (P = .03). Patients without previous experience with extraction had more concerns about anesthesia techniques (P = .02) or the number of teeth that would be removed during the same procedure (P = .02). Other questions and misconceptions were not different between these groups. CONCLUSIONS: Patients with a history of tooth extraction and those without it presented different patterns of knowledge about third molar surgery. Both groups of patients needed detailed perioperative instructions about the procedure. These results may provide oral and maxillofacial surgeons with useful information about patients' knowledge throughout the surgical process.