Effect of Polymerization on the Color of Resin Composites.

OBJECTIVES: The initial shade of a resin-based restorative material should be the same as that after polymerization. In this study, the color changes of translucent and opaque composites from nine different brands were assessed after polymerization using a spectrophotometer and cross-polarization (CP) photography. METHODS AND MATERIALS: Thirteen nano-hybrid (Essentia LE, GC Corp; Ceram.x Duo SphereTEC A2E/A2D, Dentsply Sirona; Harmonize A2E/A2D, Kerr Dental; IPS Empress Direct A2E/A2D, Ivoclar Vivadent; Mosaic EN/A2, Ultradent Products; Clearfil Majesty Es-2 A2E/A2D, Kuraray Noritake; Charisma Topaz A2/OL, Kulzer), two supra nano-hybrid (Estelite Asteria NE/A2B; Tokuyama), two nano-filled (Filtek Ultimate A2E/A2D; 3M) light-curing resin composites, and one micro-hybrid (Essentia MD, GC Corp) light-curing resin composite were tested. Disc-shaped specimens (n=5) were prepared using silicone molds (12 × 5 mm) and polymerized from both sides using an LED curing light (Elipar Deepcure S, 3M) at a light intensity of 1470 mW/cm2. Measurements were performed before and 1 day after polymerization using a contact-type dental spectrophotometer (Easy Shade 5, VITA Zahnfabrik, Bad Säckingen, Germany) and a combination of CP photography and Photoshop CC software (Adobe Inc, San Jose, CA, USA). Spectrophotometry and CP photography ΔE* values were calculated; the perceptibility threshold was a ΔE* value of 1.2. VITA spectrophotometry color change scores were also calculated and evaluated. RESULTS: The overall ΔE* values ranged between 0.34 and 12.56. Two-way analysis of variance (ANOVA) showed that color change was associated most strongly with composite brand (p<0.001), followed by shade (p=0.002). Color change (p=0.002) and degree of darkening/lightening (p<0.001) were significantly greater for dentin compared to enamel shades. Clearfil Majesty Es-2 (Kuraray Noritake) showed significant lightening, whereas all other composites showed darkening after polymerization. All composite brands presented perceptible (ΔE*≥1.2) color changes. Estelite Asteria (Tokuyama), Ceram.x Duo SphereTEC (Dentsply Sirona), and Harmonize (Kerr Dental) were considered the most reliable brands regardless of the shade. The spectrophotometry and CP photography methods were positively correlated (p<0.001). Also, CIEDE2000 and CIELCH (also referred to as CIE L*c*h) color systems were positively correlated based on the ΔE* values (p<0.001). CONCLUSIONS: Despite improvements in the chemical composition of, and fillers for, contemporary resin-based composites (RBCs), all tested composite brands showed perceptible color change after polymerization, except for some shades. Under the conditions in this study, it is preferable to polymerize the composite during the trial phase, before identifying the most appropriate shade. CP photography in combination with Photoshop analysis appears to be a reliable and promising approach for color evaluation.

Evaluation of cone beam computed tomography referral profile: Retrospective study in a Turkish paediatric subpopulation.

AIM: Increasing use of cone beam computed tomography (CBCT) for dentomaxillofacial diagnosis raises concerns about radiation dose which is known to be higher compared to conventional dental imaging methods. This retrospective study investigated the CBCT referrals in a Turkish paediatric subpopulation in terms of referring department, field of view (FOV),and findings. MATERIALS AND METHODS: A total of 8,880 CBCT images were reviewed retrospectively and images of paediatric patients (?14 years old) were selected. In paediatric patients; data related to patient age and gender, referring department, FOV, region of interest for localised applications, and reason for CBCT referral were recorded. FOVs of CBCT scans were classified as face, jaws (maxilla and mandible), maxilla, mandible, and tooth. CBCT indications were categorised based upon an adaptation of the European DIMITRA (dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks) multicenter and multidisciplinary project recommendations as impacted teeth, trauma, orofacial clefts, dental anomalies, bone pathology, syndromes, and other. Patients undergoing consecutive CBCT examinations for follow-up were also recorded. In order to record the incidental findings noticed in the CBCT evaluation, the radiological report prepared by the radiologist was used. The results were analysed statistically with a significance level set at p<0.05. RESULTS: Four hundred forty-nine of the 8880 CBCT scans were taken from paediatric patients under the age of 14, representing approximately 5% of all scans. Most of the referrals were from Department of Paediatric Dentistry (36.3%), followed by Department of Orthodontics (25.6%). The most frequently imaged region was the maxilla (33.4%), followed by the face (20.5%). The most common region of interest for localised applications was the maxillary canine/incisor region (85.55%). The most common indication was impacted teeth (41.4%) followed by bone pathology (31%) and dental anomalies (29.6%); 11.6% of the patients underwent follow-up CBCT examinations especially for orofacial clefts and syndromes. CONCLUSIONS: This retrospective study investigating CBCT indications in a Turkish paediatric subpopulation and comparing existing applications with DIMITRA project recommendations can guide dental professionals in referring paediatric patients for CBCT.

Efficacy of Endoactivator, CanalBrush, and passive ultrasonic irrigation in the removal of calcium hydroxide paste with iodoform and p-chlorophenol from root canals.

AIMS: We evaluated and compared EndoActivator, CanalBrush, and passive ultrasonic irrigation (PUI) in the removal of calcium hydroxide and calcium hydroxide with iodoform and p-chlorophenol paste (Calcipast Forte) from artificial standardized grooves in the apical third of root canals. MATERIALS AND METHODS: A total of 34 mandibular premolars were prepared and then split longitudinally. A standardized groove was prepared in the apical part of both segments. The grooves were filled with either calcium hydroxide or Calcipast Forte, and the segments were reassembled. CanalBrush, EndoActivator, or PUI were used. The amount of remaining medicament was evaluated using a four-grade scoring system. RESULTS: None of the irrigation methods could completely remove the pastes from the grooves. More Calcipast Forte paste was detected compared with calcium hydroxide (P < 0.01). PUI was the least effective method in removing Calcipast Forte. CONCLUSIONS: It was more difficult to remove Calcipast Forte than a water-based calcium hydroxide paste.

Comparison of intracoronal bleaching methods on teeth discolored by different antibiotic pastes.

AIM: To compare the bleaching efficacy of sodium perborate with different activation methods on crowns discolored by two different antibiotic pastes. MATERIALS AND METHODS: Eighty-five extracted human incisors were prepared to size #30 using ProTaper rotary instruments. After chemomechanical preparation and irrigation procedures, the specimens received triple antibiotic paste (TAP, n = 40), minocycline paste (MP, n = 40), or calcium hydroxide (n = 5, control group) and coronally sealed with temporary filling material. Spectrophotometric readings were obtained on day 0-week 4. Data were analyzed with the Mann-Whitney U-test and Wilcoxon sign test (P < 0.05). Sodium perborate was then inserted into the pulp chambers of discolored teeth (four subgroups, n = 10) and activated by heat or ultrasonically using two different frequencies and times. Spectrophotometric readings were obtained on days 3-7. Data were analyzed by the Mann-Whitney U-test and Kruskal-Wallis test (P > 0.05). RESULTS: Both groups showed statistically significant coronal discoloration at each time interval (P < 0.01), but their final shades did not significantly differ between the groups (P > 0.05). Although the MP subgroups exhibited more bleaching than the TAP subgroups on days 3 and 7, the difference was not significant (P > 0.05). The bleaching results for the sodium perborate activation techniques did not significantly differ among groups (P > 0.05). CONCLUSIONS: Both antibiotic pastes induced crown discoloration that was reversible using all sodium perborate bleaching techniques.

Evaluation of Radiopacity of Bulk-fill Flowable Composites Using Digital Radiography.

New flowable composites that may be bulk-filled in layers up to 4 mm are indicated as a base beneath posterior composite restorations. Sufficient radiopacity is one of the several important requirements such materials should meet. The aim of this study was to evaluate the radiopacity of bulk-fill flowable composites and to provide a comparison with conventional flowable composites using digital imaging. Ten standard specimens (5 mm in diameter, 1 mm in thickness) were prepared from each of four different bulk-fill flowable composites and nine different conventional flowable composites. Radiographs of the specimens were taken together with 1-mm-thick tooth slices and an aluminum step wedge using a digital imaging system. For the radiographic exposures, a storage phosphor plate and a dental x-ray unit at 70 kVp and 8 mA were used. The object-to-focus distance was 30 cm, and the exposure time was 0.2 seconds. The gray values of the materials were measured using the histogram function of the software available with the system, and radiopacity was calculated as the equivalent thickness of aluminum. The data were analyzed statistically (p<0.05). All of the tested bulk-fill flowable composites showed significantly higher radiopacity values in comparison with those of enamel, dentin, and most of the conventional flowable composites (p<0.05). Venus Bulk Fill (Heraeus Kulzer) provided the highest radiopacity value, whereas Arabesk Flow (Voco) showed the lowest. The order of the radiopacity values for the bulk-fill flowable composites was as follows: Venus Bulk Fill (Heraeus Kulzer) ≥ X-tra Base (Voco) > SDR (Dentsply DeTrey) ≥ Filtek Bulk Fill (3M ESPE). To conclude, the bulk-fill flowable restorative materials, which were tested in this study using digital radiography, met the minimum standard of radiopacity specified by the International Standards Organization.

Assessment of the periapical health of abutment teeth: A retrospective radiological study.

AIM: The aim was to examine the technical quality of root fillings and periapical status of root-filled and nonroot-filled teeth restored with crowns and bridge retainers through a retrospective analysis of orthopantomographs (OPTGs) in an adult Turkish subpopulation. MATERIALS AND METHODS: In this study, the digital OPTGs of adult patients between the ages of 20 and 70 who appealed to the Endodontics Endodontics Department of the Dentistry Faculty at Marmara University (Istanbul, Turkey) for the first time to have their endodontic treatment needs met were used. The periapical health of all teeth restored with crowns and bridge retainers, and the technical quality of the root fillings on abutment teeth were evaluated by radiographic criteria. RESULTS: The survey was carried out using the OPTGs of 1000 adult patients composed of 590 (59.0%) women and 410 (41.0%) men. 4656 (20.9%) of the totally examined 22280 teeth were with crowns and bridge retainers. 986 of the total abutment teeth were root-filled and 458 (46.5%) of them had apical periodontitis (AP) while 3670 of the total abutment teeth were nonroot-filled and 930 (25.3%) of them were with AP. The most commonly treated teeth were premolars (33.8%), followed by molars (26.2%), incisors (23.3%) and canines (16.7%). Technical quality was proved to be adequate in 27.5% of the root fillings. A higher frequency of AP was related to inadequate root fillings (P<0.01). CONCLUSION: The frequency of root-filled abutment teeth with AP, nonroot-filled abutment teeth with AP, and technically inadequate root-fillings among teeth with crowns and bridge retainers was high in the selected adult population.

Retrospective radiological assessment of root canal treatment in young permanent dentition in a Turkish subpopulation.

AIM: To determine the technical quality of root fillings as well as the periapical status of root filled teeth and non-root filled teeth in young permanent dentitions using a retrospective analysis of orthopantomographs (OPTGs) in a Turkish subpopulation. METHODOLOGY: Included in this study were the digital OPTGs taken as a part of diagnostic and planning procedures for all 19-year-old adolescents who attended the Faculty of Dentistry, Marmara University (Istanbul, Turkey) for the first time during the period from June 2007 to May 2009. The periapical status of all teeth and the technical quality of the root fillings were assessed by radiographic criteria. Statistical analysis was performed by the Mann-Whitney U, chi-squared, Fisher's exact and Cohen's kappa tests. RESULTS: The survey involved OPTGs of 1077 19-year-old adolescents: 663 (61.6%) women and 414 (38.4%) men. Of the 28974 teeth examined, 459 (1.6%) were root filled, of which 193 (42.0%) had radiological signs of apical periodontitis (AP), and 454 (1.6%) were non-root filled teeth with AP. No significant difference was found between women and men regarding the number of teeth present, the number of root filled teeth and the number of non-root filled teeth with AP (P>0.05). The most commonly treated teeth were molars (54.2%), followed by pre-molars (27.0%) and incisors (18.8%). Length was adequate in 57.3%, and homogeneity was adequate in 50.5% of the root fillings. Statistically, both the length and the homogeneity of the root fillings were significantly associated with periapical status individually (P<0.01). The overall technical quality was inadequate in 60.1% of the root fillings, and 67.0% of these were associated with signs of AP. Amongst root filled teeth, the frequency of AP in connection with molars was significantly higher (57.0%) than that for incisors (27.9%) and pre-molars (21.8%) (P<0.01). CONCLUSIONS: The results of this study indicated that the frequency of root filled teeth with AP, non-root filled teeth with AP and of technically inadequate root fillings amongst all root filled teeth was high in this selected adolescent Turkish population.