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Language Journal of Clinical and Experimental Dentistry. 2018. Vol. 10, no. 8
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- Effect of sintering process on color parameters of nano-sized yttria partially stabilized tetragonal monolithic zirconia(2018) Juntavee, Niwut; Attashu, SurawutSintering process is responsible for aesthetic of zirconia restoration. This study evaluated the effect of different sintering temperatures and sintered-holding times on color parameters of monolithic zirconia. One hundred and thirty five zirconia bar specimens (width-length-thickness = 10×20×1.5 mm) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic and randomly divided into nine groups to be sintered at different temperatures [decreasing- (SD, 1350°C), regular- (SR, 1450°C), and increasing- (SI, 1550°C) sintering temperature] and different sintered-holding times [shortening- (HS, 60 min), regular- (HR, 120 min), and prolonged- (HP, 180 min) sintered-holding time]. Color appearance (?E), translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) were determined with spectrophotometer. An analysis of variance (ANOVA) and Tukey?s multiple comparisons were used to determine for statistically significant difference of color parameters (?=0.05). Crystal sizes were microscopically examined using scanning electron microscope (SEM), and phase composition of zirconia was determined using X-ray diffraction (XRD). The mean±sd for ?E, TP, CR, OP were 82.28±1.27, 1.4±0.13, 0.982±0.004, 1.25±0.15 for SDHS, 78.38±0.74, 2.16±0.10, 0.967±0.005, 1.90±0.11 for SDHR, 74.43±0.91, 2.24±0.10, 0.964±0.004, 1.94±0.09 for SDHP, 76.31±1.22, 3.03±0.10, 0.945±0.003, 2,50±0.09 for SRHS, 74.51±1.27, 3.19±0.17, 0.942±0.003, 2.65±0.16 for SRHR, 73.94±0.49, 3.42±0.10, 0.937±0.003, 2,83±0.09 for SRHP, 76.30±0.43, 3.16±0.09, 0.937±0.002, 2.48±0.09 for SIHS 76.73±1.15, 3.05±0.20, 0.939±0.005, 2.38±0.17 for SIHR, and 75.32±1.37, 2.95±0.18, 0.942±0.006, 2.33±0.15 for SIHP. The ?E, TP, CR, and OP were significantly affected by altering sintering temperatures and holding times (p<0.05). Increasing sintering temperature and extending sintering time significantly improved color appearance, translucency, contrast, and opalescence of Y-TZP (p<0.05) as evidenced by enlarging grain size and increasing t?m phase shift. Raising sintering temperature and prolonging sintering time lead to better color appearance, translucency, contrast and opalescence of nano-sized monolithic Y-TZP, and are suggested for sintering process.
- Correlation between alteration of enamel roughness and tooth color(2018) Vieira-Junior, Waldemir-Francisco; Vieira, Isabele; Bovi Ambrosano, Gláucia MarÃa; Aguiar, Flávio Henrique Baggio; Lima, Débora Alves Nunes LeiteTo establish the correlation between enamel roughness and color change of tooth. Enamel/dentin blocks (5 x 5 x 3.2 mm) were serially ground with the following abrasive paper: 1200-grit, 800-grit, and 600-grit SiC papers. In the paired model, the analyses of color (L*, a*, b*, ?E) and roughness (Ra) were performed among the sandpaper exposure. The data were subjected to ANOVA using models for repeated measures followed by the Tukey test. The Pearson correlation test was used to determine whether there was a relationship between Ra values and color results (? = 0.05). The L* values decreased in accordance with the increase of Ra, with statistical difference between all the times (p<0.05). A correlation was found between the Ra vs. the L* values (r = -0.67; p<0.0001) and ?Ra vs. ?a* values (r = 0.29; p = 0.05); besides that, there was no significant correlation with b* values or significant alteration in the ?E values (p>0.05). The alteration of enamel roughness acted on the lightness and the green-red axis of tooth color. However, there was no significant correlation between the alteration of roughness of enamel and general color change of tooth.
- In-vivo effects of flapless osteopuncture-facilitated tooth movement in the maxilla and the mandible(2018) Haliloglu-Ozkan, Tugba; Arici, Nursel; Arici, SelimThis study aimed to investigate the effects of a minimally invasive, flapless procedure to enhance tooth movement in both jaws and to determine whether this triggers the acceleration when repeated monthly. The sample consisted of thirty-two individuals whose orthodontic treatment required canine retraction. They were divided into an experimental group and control group. Osteopunctures were performed using orthodontic mini-screws at the distal aspects of the canine teeth at the beginning and on the fourth week of distalization in the experimental group. The control group was treated with conventional mechanics. All canines were retracted. The rates of canine distalization, rotation, and tipping were measured on the first, fourth, and eighth weeks of distalization. First molar anchorage loss was also measured. Intergroup and intragroup analyses were performed. Flapless osteopuncture-facilitated tooth movement resulted in greater canine distalization and reduced molar movement in the maxilla in the experimental than in the control group during the first month of distalization. In addition, the extent of upper canine movement was significantly higher in the experimental group in the first month than in the second. No differences in canine and molar movement in the mandible were observed between the two groups. OP, as applied in this study, is an effective method for increasing the rate of tooth movement in the maxilla. Repeating the procedure monthly does not appear to show a major advance of tooth movement.
- Tridimensional assessment of the dental follicle dimensions of impacted mandibular third molars using cone-beam CT(2018) Barroso, Marlene; Arriola-Guillén, Luis-Ernesto; RodrÃguez-Cárdenas, Yalil-Augusto; RuÃz-Mora, Gustavo-Armando; Guerrero, Maria Eugenia; Flores-Mir, CarlosThe present study was performed to compare follicle dimensions of impacted mandibular third molar (IMTM) with different impaction angulations using cone beam computed tomography (CBCT). Forty-nine individuals with IMTM (24 male, 25 female) were selected. Their age range was 25-55 years. The sample was divided into three IMTM groups either vertical (n=16), mesioangular (n=18) or horizontal (n=15) position based on Winter?s classification (the angle between the longitudinal axis of the second and third molars). Follicular spaces (FS) from available CBCT imaging were measured from the midpoint of the teeth?s crown in several dimensions (mesial, distal, occlusal, apical, vestibular and lingual) in axial, sagittal and coronal planes. An ANOVA, T-student, Kruskal?Wallis and Mann-Whitney U tests were used. A comparison of the mesial FS for all groups revealed significant differences (p<0.001). Significant difference was also found for vestibular FS between the vertical and mesioangular IMTM groups (p=0.04). Buccolingual FS for all groups revealed no significant differences (p=0.074), whereas significant difference was found for the vertical and horizontal IMTM groups (p=0.02). No significant statistical differences were found for occlusal (p=0.54), apical (p=0.06), and lingual (p=0.64) FS. In this sample IMTM follicles have different dimensions according to their degree of angulation. Mesioagulated and horizontally positioned IMTMs seems to consistently have some increased FS dimensions (mesial and vestibular aspects).
- Nonsyndromic cleft lip and/or palate : a multicenter study of the dental anomalies involved(2018) Menezes, Carlos; Arruda, José A.; Silva, Leni-Verônica; Monteiro, João-Luiz; Caribé, Pérola; Alvares, Pâmella; Almeida, Maria-Cristina; Coelli, José-Carlos; Goldemberg, Fernanda; Da Silveira, Márcia MarÃa Fonseca; Sobral, Ana-Paula; Bueno, Daniela-FrancoNonsyndromic cleft lip and/or palate (NSCL/P) is the most common craniofacial malformation. Due to the anatomical defect present in the alveolar process, these patients tend to exhibit more dental anomalies. The aim of this study was to identify the prevalence of dental anomalies in patients with NSCL/P by obtaining orthodontic documentation from Brazilian Centers for cleft lip and palate treatment. A retrospective analysis (2000-2014) was conducted on orthodontic archives, radiographs and medical records of NSCL/P of 524 patients under orthodontic treatment. Panoramic radiographs and intra-oral photographs were examined to identify these anomalies. Categorical variables were expressed in terms of frequencies and percentages and analyzed using the Chi-Square test. The level of significance was set at p?0.05 in all analyses. Approximately 83.3% of the individuals had at least one dental anomaly. Tooth agenesis was the most common abnormality found in those patients (87.8%) (p<0.001). Also, the largest number of dental anomalies was detected in the group of unilateral left clefts. The prevalence of dental anomalies in the present sample of NSCL/P patients was high and reached the highest levels in patients with alveolar bone clefts. This study describes the most common dental anomalies observed in patients with NSCL/P. These abnormalities can cause significant problems that may be solved or minimized by early diagnosis and treatment.
- Effect of different bleaching protocols on whitening efficiency and enamel superficial microhardness(2018) Mushashe, Amanda Mahammad; Coelho, Beatriz-Serrato; Garcia, Paula-Pontes; Rechia, Bruna-Cristina-do Nascimento; da Cunha, Leonardo Fernandes; Correr, Gisele Maria; Gonzaga, Carla CastigliaTooth bleaching is a popular aesthetic treatment to modify the color of teeth. Despite the extensive literature concerning the subject, there is still no consensus regarding the application mode of the different bleaching agents and their effect on enamel. Therefore, this study evaluated the influence of different bleaching protocols on whitening efficiency and enamel superficial hardness. Bovine enamel fragments were embedded in acrylic resin and wet-sanded to obtain a flat buccal surface. The specimens were then randomly divided into 6 groups (n=10), based on the bleaching material [HP Maxx 35% (35% hydrogen peroxide), HP Blue 35% (35% hydrogen peroxide + Ca) and Whiteness Perfect 10% (10% carbamide peroxide)] and application mode (3 applications of 15 min, 1 application of 45 min, 1 application of 1h30 or 1 application of 3h30). The color and superficial hardness were assessed before and after bleaching. The color was assessed by means of a digital spectrophotometer, using CIELab parameters. Vickers hardness was determined using a load of 200g for 10s. Data were statistically analyzed by one-way ANOVA with repeated measures and Tukey?s test (? = 0.05). Concerning the color alteration, the groups were similar to each other, except for at-home bleaching protocols, which were statistically different from each other. Similarly, there was a reduction in hardness values comparing the initial and final periods, with lowest final hardness for the at-home bleaching protocol group applied for 3h30. It can be concluded that the bleaching protocols influenced the final color and enamel surface hardness, evidencing that lower gel concentrations applied for longer periods promoted greater variation in color and lower final hardness.
- Shear bond strength of metal brackets to ceramic surfaces using a universal bonding resin(2018) Naseh, Roya; Afshari, Maryam; Shafiei, Fereshteh; Rahnamoon, NimaAssure Plus is a recently introduced universal adhesive with the ability to bond to various restorations. This study compared the shear bond strength of brackets bonded to two types of ceramics using conventional bonding agent and Assure Plus. Surface damage caused by debonding was also evaluated. In this in vitro study, 40 feldspathic and lithium disilicate ceramic discs were sandblasted, etched with 9.6% hydrofluoric acid and divided into two groups. In group 1, silane was applied and air-dried followed by application of Transbond XT primer, which was light-cured. In group 2, Assure Plus was applied and air-dried. In both groups, maxillary central incisor brackets were bonded. After incubation in distilled water at 37°C for 24 hours and 2000 thermal cycles, bond strength was measured using a universal testing machine, and the adhesive remnant index (ARI) and failure modes were determined. ANOVA and LSD tests were used to compare bond strength values; chi-squared test was used to compare ARI scores. Bracket bond to lithium disilicate by Assure Plus was significantly stronger than that to Feldspathic porcelain (P=0.041). Only in the Assure Plus/lithium disilicate group did some adhesive remain on the surface following debonding (40% of samples, P<0.05). Cohesive porcelain fracture had the lowest frequency in the lithium disilicate/Assure Plus group. Assure Plus provided high bond strength between ceramic and brackets and minimized damage to lithium disilicate ceramic during debonding. Assure Plus is recommended for use in orthodontic treatment of adults with ceramic restorations.
- Effect of different sintering process on flexural strength of translucency monolithic zirconia(2018) Juntavee, Niwut; Attashu, SurawutSintering process is responsible for the strength of zirconia restoration. This study evaluated the effect of different sintering temperatures and sintered-holding times on flexural strength of translucency monolithic zirconia. One hundred and thirty five zirconia bar specimens (width-length-thickness = 10×20×1.5 mm) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic and randomly divided into nine groups to be sintered at different temperatures [decreasing- (SD, 1350°C), regular- (SR, 1450°C), and increasing- (SI, 1550°C) sintering temperature] and different sintered-holding times [shortening- (HS, 60 min), regular- (HR, 120 min), and prolonged- (HP, 180 min) sintered-holding time]. Flexural strength was determined using three-point bending test in a universal testing machine at 1 mm/min crosshead speed. An analysis of variance (ANOVA) and Tukey?s multiple comparisons were used to determine for statistically significant difference of flexural strength (?=0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (?o) of the flexural strength. The crystal sizes were microscopically examined using scanning electron microscope (SEM). The phase composition of zirconia was determined using X-ray diffraction (XRD). The mean±sd (MPa), m, and ?o of flexural strength were 1080.25±217.19, 5.54, and 1167.53 for SDHS, 1243.41±233.17, 5.19, and 1352.30 for SDHR, 1298.92±235.68, 6.24, and 1394.79 for SDHP, 1303.34±171.87, 8.40, and 1377.90 for SRHS, 1331.73±278.84, 5.31, and 1444.50 for SRHR, 1348.13±283.35, 5.32, and 1460.68 for SRHP, 1458.45±289.19, 4.51, and 1604.41 for SIHS 1581.34±190.56, 8.20, and 1675.21 for SIHR and, 1604.10±139.52, 12.57, and 1667.90 for SIHP. The flexural strength was significantly affected by altering sintering temperatures and holding times (p<0.05). Enlarging grain size and increasing t?m phase shifting related with raising temperatures and times. Increasing sintering temperature and prolonged sintered-holding time lead to enhancing flexural strength of translucency monolithic zirconia, and are suggested for sintering process to achieve durable restoration.
- Effects of different etching strategies on the microtensile repair bond strength of beautifil II giomer material(2018) Bahari, Mahmood; Savadi Oskoee, Siavash; Kimyai, Soodabeh; Savadi-Oskoee, Ayda; Abbasi, FarhangConsidering the differences in the filler particles between giomer and conventional composite resins and the importance of these fillers in the repair bond strength, the aim was to evaluate the effects of different etching strategies with phosphoric acid (PA) and hydrofluoric acid (HF) on the microtensile repair bond strength (µTRBS) of giomer. Ten giomer blocks were randomly assigned into 10: 1) control; 2) 37%PA-20s; 3) 3%HF-20s; 4) 3%HF-120s; 5) 9.6%HF-20s; 6) 9.6%HF-120s; 7) 37%PA-20s + 3%HF-120s; 8) 37%PA-20s + 9.6%HF-120s; 9) 3%HF-120s + 37%PA-20s; 10) 9.6%HF-120s + 37%PA-20s. In all groups, the One-Step Plus bonding system was applied and the new giomer block was bonded to the existing giomer. After cross-sectional cutting, 18 samples were prepared from each block and the µTRBS of the samples was measured at a strain rate of 0.5 mm/min. Data were analyzed with one-way ANOVA and post hoc Tukey tests (P<0.05). The µTRBS in groups 4, 5, 6, 7, 8 and 10 were significantly higher than that in the control group (P<0.05). The µTRBS in group 2 was even less than that in the control group (P<0.001). The highest µTRBS was recorded in group 10, which was significantly different from those in groups 3, 4 and 9 (P<0.05). In addition, the differences between group 9 and groups 6, 7 and 8 were significantly different (P<0.05). Etching with PA resulted in a decrease in µTRBS. Etching with HF, except for 3%HF-20s and HF after etching with PA, resulted in a significant increase in giomer`s µTRBS. An increase in the application time of 3%HF resulted in a significant increase in the µTRBS.
- An in vitro cyclic fatigue resistance comparison of conventional and new generation nickel-titanium rotary files(2018) Ruiz Sánchez, Celia; Faus Matoses, Vicente; Alegre Domingo, Teresa; Faus Matoses, Ignacio; Faus Llácer, VicenteNew designs and processing of Niquel-Titanium (NiTi) have been introduced to increase resistance to cyclic fatigue. The purpose of this study was to compare the cyclic fatigue resistance of 3 NiTi rotary instruments, ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Profile Vortex Blue (PVB; Dentsply Tulsa Dental, Tulsa, OK, USA) and ProTaper Universal (PTU; Dentsply Maillefer, Ballaigues, Switzerland). A cyclic fatigue test was conducted operating instruments from ProTaper Next X2, Profile Vortex Blue 25.06 and ProTaper F2. A total of 234 instruments were rotated in 2 simulated stainless steel curved canals with different angles of curvature (45º and 60°) and 5-mm radius of curvature. The number of cycles to fracture (NCF) was calculated. Data were compared using 2-way analysis of variance and post-hoc Bonferroni test in software (SPSS 15.0, Chicago, IL). Statistical significance was set at P<0.05. Profile Vortex Blue showed higher resistance to cyclic fatigue in both curved canals than ProTaper Next and ProTaper Universal (P<0.001). ProTaper Universal obtained the lowest resistance to cyclic fatigue in both canals (P<0.001). Profile Vortex Blue was the most resistant to cyclic fatigue failure, followed by ProTaper Next and ProTaper Universal. Anatomical complexity (angle of curvature) and manufacturing process of NiTi are important factors for resistance to cyclic fatigue.
- Comparison of three adhesive systems in class II composite restorations in endodontically treated teeth : influence of Er:YAG laser conditioning and gingival margin levels on microleakage(2018) Onay, Emel-Olga; Yamanel, Kivanc; Korkmaz-Ceyhan, Yonca; Gulsahi, KamranDental surface conditioning by Er:YAG laser is currently being investigated, as not all of the mechanisms and effects of this technique have been clearly studied. Thus, the aim of the present study was to assess the cervical microleakage of Class II resin composite restorations in endodontically treated teeth following either the respective conventional conditioning or additional Er:YAG laser conditioning, in association with varied adhesives. Standardized mesial-occlusal-distal cavities (two gingival walls positioned in dentin and enamel, respectively) were created in 60 extracted human premolar teeth. Following the completion of the endodontic therapy, the teeth were grouped into six categories based on conditioning modality and adhesive strategy as follows: group 1-37% phosphoric acid/Adper Single Bond 2 (ASB2); group 2-Er:YAG laser/37% phosphoric acid/ASB2; group 3-Clearfil SE Bond (CSE); group 4-Er:YAG laser/CSE; group 5-Adper Easy One (AEO); and group 6-Er:YAG laser/AEO. Specimens were submitted to thermocycling and dye penetration, followed by longitudinal sectioning. The dye penetration was evaluated using a stereomicroscope. One specimen from each group was assessed under a scanning electron microscope for adhesive interface analysis. No significant differences were found between the conditioning modalities, nor between the adhesive systems at both margins. Groups 1 and 2 showed a lower degree of microleakage in the enamel vs. dentin (p = 0.002). Group 2 showed a significantly lower incidence of microleakage in enamel vs. dentin (p = 0.005). CSE and AEO were comparable with that of ASB2 regarding sealing ability. Additional Er:YAG laser conditioning may be beneficial before ASB2 application in enamel.
- Anti-erosive effect of calcium carbonate suspensions(2018) Scandiffio, Priscila; Mantilla, Tais; Amaral, Flávia; França, Fabiana; Basting, Roberta; Turssi, CeciliaThis study aimed to investigate the ability of different concentrations of calcium carbonate (CaCO3) suspensions to control enamel surface loss. Seventy-five enamel slabs were embedded, ground and polished in a pneumatic grinder-polisher machine. Reference areas were created with UPVC tape and the specimens were randomly allocated into five groups (n = 15) for exposure to hydrochloric acid solution to simulate gastric juice (0.01 M, pH 2) for 2 minutes. The samples were then exposed to suspensions containing 0.0001, 0.001, 0.01 or 0.1 mmol/L CaCO3 for 1 minute. Artificial saliva was used as control. The samples were subjected to a total of five erosive cycles followed by treatment with CaCO3 suspension. Surface loss was measured (in µm) using optical profilometry. One-way ANOVA (p = 0.009) and Tukey?s test showed a significant reduction in surface loss when compared to the group not exposed to CaCO3 (0.74, +/- 0.23 µm), and the 0.01 mmol/L (0.40; +/- 0.23 µm) and 0.1 mmol/L suspensions (0.37; +/- 0.26 µm). The lower concentrated suspensions were incapable of significantly reducing enamel surface loss. Rinsing with 0.01 and 0.1 mmol/L calcium carbonate suspensions was revealed as a potentially promising strategy to prevent enamel erosion.
- Non syndromic synchronous multiple odontogenic keratocysts in a western Indian population : a series of four cases(2018) Sundaragiri, Krishna-Sireesha; Saxena, Shikha; Sankhla, Bharat; Bhargava, AkshayOdontogenic keratocysts (OKCs) are developmental odontogenic cysts affecting the maxillofacial region and their association with a syndrome especially Naevoid basal cell carcinoma syndrome (NBCCS) is a common occurrence in comparison to non syndromic multiple OKCs. In a first, we present a series of four non syndromic cases with multiple OKCs in western Indian population. The presence of multiple OKC in our present case series may be because of the multifocal nature of the lesion rather than its association with any syndrome. Thus, a comprehensive evaluation of any patients reporting with multiple cysts/OKCs always has to be undertaken and the dental practitioner may be the play a key role in early detection and subsequent follow-up.
- Study of the influence of crossbite on the size of the apical area in a child population by analyzing panoramic X-ray(2018) RodrÃguez Peinado, Nazareth; Diéguez Pérez, Montserrat; Saavedra Marbán, Gloria; Mourelle MartÃnez, Mª RosaThe apical area is the space in the maxillary bones that contains teeth during formation and is subsequently occupied by the apices of the permanent teeth. Its dimensions are easy to perceive and determine by observing a panoramic X-ray. Our objective was to analyze the influence of crossbite on the size of the anterior and mesial apical area in Caucasian children. Based on the ortopantomograph of 353 patients in mixed dentition and crossbite, the sizes of the apical areas of the four hemiarches were studied using the Tps Dig Version 2® computer program. These data were subjected to statistical analysis using the SPSS 22.0 for Windows program and applying the methods of descriptive statistics of quantitative variables, the Kolmogorov-Smirnov test, the non-parametric test Mann-Whitney-Wilcoxon test, and the paired Student t-test. In the group of boys, average values in the superior-mesial, superior-anterior, inferior-mesial and inferior-anterior apical areas of the crossbite were 173.43, 99.85, 180.32 and 87.56 respectively, with the lower values being in the hemiarch without malocclusion. In the group of girls, for the same apical areas, average values were 165.64, 94.24, 168.62 and 83.34 respectively, with all the highest values being in the hemiarch with crossbite, except for the inferior-mesial apical area. Statistically significant differences were found in the hemiarch with crossbite between both genders in the superior-anterior, inferior-anterior and inferior-mesial apical areas, with the significance being 0.001, 0.029 and 0.001 respectively, while in the hemiarch without malocclusion significance was observed in the superior-mesial, superior-anterior and inferior-mesial apical areas, with values of 0.004, 0.001 and 0.004, respectively. Crossbite affects the size of the anterior apical area in both arches and in both genders. The mesial apical area is influenced by this malocclusion in the jaw in boys and in the maxilla girls.
- Evaluation of the time required to perform three retreatment techniques with dental microscope and ultrasonic activation for removing filling material from the oval root canal(2018) Alakabani, Tarek-Fahed; Faus Llácer, Vicente; Faus Matoses, VicenteWhen endodontic treatment fails, retreatment consists of the complete removal of the root canal filling material for thorough cleaning and reobturation. Various techniques are available for the filling removal procedure, which present varying degrees of efficacy, and take a varying length of time to perform. The aim of this study was to compare the time required to carry out reciprocating, rotary, and manual techniques with dental microscope and ultrasonic activation for removing filling material from root canals. Ninety-nine extracted single-rooted teeth with straight and oval-shaped canals were selected. The samples were instrumented with ProTaper Gold System up to file F2 and obturated with AH Plus sealer and GuttaCore. The teeth were randomly divided into three groups (n=33) according to the instruments used for removal of filling material: Group (1) Reciproc blue R50 instrument; Group (2) ProTaper Retreatment instruments; Group (3) manual (Hedstrom files and Gates-Glidden drills), under dental microscope at X10 magnification with Ultrasonic retreatment tip. The time required to remove the filling materials was measured with a chronometer. Data were analyzed statistically applying the Kruskal-Wallis test followed by the Mann-Whitney U-test (p<0.05). The time required to remove filling material was significantly shorter in Group 1, followed by Group 2, the slowest being Group 3 (P<0.05). The reciprocating technique was the fastest method for removing root canal filling material.
- Criteria and treatment decisions in the management of deep caries lesions : is there endodontic overtreatment?(2018) Crespo-Gallardo, Isabel; Hay-Levytska, Olesia; MartÃn González, Jenifer; Jiménez Sánchez, MarÃa del Carmen; Sánchez DomÃnguez, Benito; Segura-Egea, Juan J.The aim of this study was to investigate the diagnostic criteria and treatment decisions in the management of deep caries lesions (DCLs). The null hypothesis tested was that DCLs are managed according to the current scientific evidence. A total of 288 dentists were contacted directly or by mail, and 125 (43%) were included in the study. Dentists were requested to answer a questionnaire about the routine approach to the diagnosis and treatment of DCLs. Logistic regression analyses were carried out to calculate odds ratios (OR). Pulp sensitivity tests were used by 65% of dentists when assessing pulpal health in cases of DCLs, particularly those who had followed courses in cariology (OR = 3.8; p = 0.005). Dentine hardness was the most frequent criterion used during DCLs excavation (98%). Two thirds of the respondents (65%) removed carious tissue until they felt hard dentine, and feeling hard dentine correlated with caries removal even at the risk of pulpal exposure (OR = 15.8; p = 0.0000). Acute transient pain or sensitivity to cold or heat (reversible pulpitis) were considered by 58% of respondents as a reason to provide endodontic therapy. The null hypothesis tested is rejected. The evidence-based more conservative approach on the management of DCLs is not being translated to clinical dentistry. Root canal treatment is being indicated in cases of DCLs in which the diagnosis is reversible pulpitis. Likewise, it can be concluded that non-conservative management of DCLs, with endodontic overtreatment, could be occurring.
- The effect of orthodontic bracket pad shape on shear bond strength, an in vitro study on human enamel(2018) Patel, Nirav; Bollu, Prashanti; Chaudhry, Kishore; Subramani, KarthikeyanTo evaluate the effect of bracket pad shape on shear bond strength (SBS) of orthodontic brackets bonded to human enamel. One hundred and five extracted human maxillary permanent molars were divided into 7 groups of 15 specimens per group (n=15). Each group of teeth was bonded with 6 different shaped WildSmiles® brackets (Star, Heart, Soccer ball, Football, Flower, and Diamond) and GAC® rectangle shaped brackets. Shear debonding force was measured with an Instron universal testing machine using a knife-edged chisel 24 hours after initial bonding. Descriptive statistics (mean, standard deviation, and range) for each bracket pad shape was calculated. Analysis of variance (ANOVA) using SPSS software version 24.0 was performed with P-value set at 0.05. Post-Hoc Tukey analysis was used to analyze differences among groups. Differences in Adhesive Remnant Index (ARI) scores among groups were analyzed using Chi-square test. Debonding force values (N ± SD) ranged from 205.51 ± 49.12 (Star) and 275.96 ± 69.05 (Soccer). SBS values (MPa ± SD) ranged from 13.34 ± 3.18 (Star) and 17.77 ± 6.94 (Rectangle). Even though intergroup comparison of SBS in Newtons revealed statistical significance (p = 0.014) between Star-Soccer and Star-Football group, it does not have any clinical significance since ranges of SBS of all groups are clinically acceptable. Analysis of ARI scores showed no significant differences in mode of bond failure among groups (P = 0.82). Orthodontic bracket pad shape has no effect on SBS and does not affect the mode of fracture pattern.
