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Language Journal of Clinical and Experimental Dentistry. 2018. Vol. 10, no. 6
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- Comparison of spring characteristics of titanium-molybdenum alloy and stainless steel(2018) Sheibaninia, Ahmad; Salehi, Anahita; Asatourian, Armen
- Effect of surface treatments on the bond strength of CAD/CAM fiberglass posts(2018) Garcia, Paula-Pontes; da Costa, Rogério Goulart; Garcia, André-Vivan; Gonzaga, Carla Castiglia; da Cunha, Leonardo Fernandes; Rezende, Carlos-Eduardo-Edwards; Correr, Gisele MariaBackground: There is no ideal protocol for the surface treatment of fiber posts, especially when using a computer-aided design/computer-aided manufacturing (CAD/CAM) experimental fiberglass block. The purpose of this study was to evaluate the bond strength of a CAD/CAM customized glass fiber post and core after applying different surface treatment techniques. Material and Methods: Forty premolars were prepared to receive a customized CAD/CAM glass-fiber post and core obtained from an experimental block of glass fiber and epoxy resin. The specimens were randomly distributed in 4 groups (n=10) according to the post and core surface treatment: ETH - 70% ethanol; HP - 24% hydrogen peroxide for 1 minute; ETH/S - 70% ethanol + silane; HP/S - 24% hydrogen peroxide + silane. The universal adhesive containing silane was applied on the posts and prepared post spaces in all groups. The posts were cemented using dual cure resin cement. The specimens were stored in distilled water at 37°C for 24 h, cut (two slices of 1 mm for each root third - coronal, middle, and apical) and subjected to push-out test (0.5 mm/min). Data was subjected to two-way ANOVA (surface treatment and root third) and Tukey?s test (?=0,05). Results: There was no significant difference of bond strength values among groups, regardless the surface treatment ( p >0.05). There was significant difference on bond strength values for the different root thirds ( p <0.05) (coronal> - middle=apical). Conclusions: The different surface treatment and application of additional silane in the CAD/CAM customized glass-fiber post and core does not interfere on bond strength values. The root dentin third interfered on the bond strength, with higher values for the coronal third.
- Implant survival in patients with oral cancer : a 5-year follow-up(2018) Flores Ruiz, Rafael; Castellanos Cosano, Lizett; Serrera Figallo, María Angeles; Cano Díaz, Eloy; Torres Lagares, Daniel; Gutiérrez Pérez, José LuisBackground: To evaluate the evolution of patients rehabilitated with endosseous implants after oral cancer treatment. Material and Methods: An observational retrospective study was carried out between 1991 and 2011 with a sample consisting of patients with oral cancer who had been referred for rehabilitation to the Prosthetics Rehabilitation Unit from the Oral and Maxillofacial Surgery Unit of the Virgen del Rocío University Hospital. All these patients have overcome oral cancer, and have a five-year follow-up after their oral rehabilitation. Age, sex, smoking habits, oral pathology, type of treatment of oral pathology, edentulism, receptor bone, prosthetic rehabilitation, timeouts, working time and evolution were studied. SPSS Statistics was used for statistical analysis of the variables studied. A chi-square test centered on the survival rate of implants placed in relation to the other recorded variables was performed. Results: 17 patients were treated for cancer and rehabilitated with implant prosthetics, with a total of 106 implants placed. 32% were partially edentulous patients (4 patients), and 68.2% were completely edentulous patients (13 patients). An implant survival rate of 87.7% was observed at 5 years. In the upper maxilla, the survival rate was 79.2%, and in the mandible 93.7% ( p = 0.03). 91 implants were placed in native receptor bones (85.8%), with only 15 implants placed in grafted receptor bone (14.2%). According to the type of receptor bone, in native receptor bones, 9 implants failed (90.1% of implant survival), while in grafted receptor bones, 4 implants failed (overall 73.3% implant survival rate) ( p = 0.08). Conclusions: Although a high survival rate was obtained in this study (with lower survival rates seen in mandible and grafted bone), prospective long-term studies are needed to assess the relationship between radiotherapy doses and the time required for implant placement, prosthetic protocol used, and type of implants used in patients selected for prosthetic rehabilitation.
- Root canal treatment of dilacerated second maxillary premolars : planning the shaping procedure(2018) Mancino, Davide; Kharouf, NajiThis article aims at investigating endodontic anatomical variants in the human maxillary premolars allowing the planning of safer and faster shaping procedures. Endodontic literature describes maxillary 2nd premolars as some of the easiest teeth to treat, as they have either one or two straight canals. Rarely they may sometimes have two dilacerated canals. This paper reports two clinical cases of maxillary premolars whose anatomy is quite unusual. In the first case report we describe a maxillary 2nd premolar with a single root and two dilacerated merged canals. The second case report concerns the retreatment of a maxillary 2nd premolar with a single root and two independent dilacerated canals, and even some lateral canal. In dilacerated anatomy, canal scouting step might cause some procedural errors. To avoid these procedural errors, we propose a modern step down technique using at first a rotary NiTi glide path instrument, to go up to the 2/3 of root canal length or until to the first impediment. This would allow an easy apical scouting of the last millimeters of endodont and increase the volume of the irrigants in the apical region. In this way since a safer and faster shaping procedure could be performed
- Is dental plaque the only etiological factor in Amlodipine induced gingival overgrowth? A systematic review of evidence(2018) Gaur, Sumit; Agnihotri, RupaliBackground: Amlodipine, a dihydropyridine calcium channel blocker (CCB) is commonly prescribed for cardiovascular conditions. Its administration may produce an uncommon adverse oral manifestation, the gingival overgrowth (GO). Lately, there has been an increase in the rate of GO in patients on amlodipine therapy. The current systematic review was undertaken to evaluate the evidence on plausible risk factors involved in amlodipine induced gingival overgrowth (AIGO). Material and Methods: Literature search was conducted in the databases like Pubmed (Medline), Scopus and Google Scholar to include the original research articles related to etio-pathogenesis of AIGO. Results: About 270 documents were identified through primary search, of which 13 original research articles were included. Most common risk factor for AIGO was administration of amlodipine in subjects with poor plaque control. However, high dosage of drug, duration of therapy and inherent genetic susceptibility were recognized as other plausible risk factors. Conclusions: It was concluded that AIGO is no longer a rare phenomenon. It is therefore imperative for the physician to identify and inform patients, about the risk factors associated with the overgrowth at the initiation of therapy. This would prevent the development of GO?s and improve the patient?s quality of life
- Management of a crown-root fracture : a novel technique with interdisciplinary approach(2018) Artieda-Estanga, Amaia; Castelo Baz, Pablo; Bello Castro, A.; Ramos Barbosa, Isabel; Martín Biedma, Benjamín; Blanco Carrión, JuanAnterior teeth with subgingival fractures require a complex treatment plan that addresses biologic, functional and aesthetic factors. This case report describes the management of a crown-root fractured maxillary left central incisor. An interdisciplinary approach was used to restore the tooth due to the complex nature of the treatment. Orthodontic extrusion was performed to move the fracture line above the alveolar bone and periodontal surgery to recontour the altered gingival margin. Finally, the incisor was restored performing a root canal retreatment with a fiber post and a full ceramic crown. The treatment resulted in secured periodontal health and good aesthetics
- Comparative study of debris and smear layer removal with EDTA and Er,Cr:YSGG laser(2018) Montero-Miralles, Paloma; Torres Lagares, Daniel; Segura-Egea, Juan J.; Serrera Figallo, María Angeles; Gutiérrez Pérez, José Luis; Castillo Dalí, GabrielBackground: To evaluate in vitro , the ability in removing debris and Smear Layer of 17% EDTA and Er,Cr:YSGG laser. Material and Methods: 58 unirradicular teeth were instrumented with MTwo® and divided into 3 groups according to irrigation protocol: 17%EDTA, laser and a combination of 17%EDTA and laser. All samples were analyzed in the apical and middle third with Scanning Electron Microscope. The Chi-cuadrado and McNemar tests were used to determine the statistical analysis and data processing and analysis was performed with the statistical package StatGraphics Centurion XVI. Results: Debris analysis showed statistical significant differences when compared EDTA vs laser and EDTA vs EDTA+laser in the middle third. The Smear Layer removal showed statistical significant differences in the middle third when compared EDTA vs laser and EDTA vs EDTA+laser. Conclusions: Laser showed a greater cleaning capacity than EDTA in the middle third; the cleanliness was even better when combined laser with EDTA, so the effect is accumulative.
- Histopathologic analysis of gingival lesions : a 20-year retrospective study at one academic dental center(2018) Alblowi, Jazia A.; Binmadi, Nada O.Background: The gingiva is part of the periodontium supporting structures surrounding the teeth and commonly involved in gingival and periodontal conditions. Assessing the distribution of gingival lesions is important for evaluating the prevalence of periodontal disease in the population to optimize the oral health care services. The purpose of this study is to report the frequency and distribution of gingival lesions biopsied from 1996?2016. Material and Methods: This cross-sectional retrospective study retrieved data from all gingival lesions biopsied from 1996?2016 and sent to the King Abdulaziz University Dental Hospital oral pathology laboratory. Histologic sections were reviewed in a blinded manner by a certified oral pathologist to confirm the initial histologic diagnosis. Results: Of the 1,248 oral-maxillofacial lesions, 119 (9.5%) gingival lesions were diagnosed. The mean age was 41.58 years. Gingival lesions were more prevalent in female patients than male patients (53.8%). The most common diagnoses were reactive lesions (41.2%). Pyogenic granuloma was the predominant lesion in the category (n=26, 21.8%), and followed by inflammatory conditions (24.4%), benign neoplasm (9.2%), malignant neoplasm (7.6%), epithelial lesions (7.6%), miscellaneous (5%), and immune-mediated diseases (5%). Squamous cell carci noma was the only malignant neoplasm reported (7.6%; mean age, 57.44 years) and more common in male than female patients (2:1). Most biopsies were sent from oral and maxillofacial surgeons (55.6%) followed by general dentists (22.2%) and periodontists (12.8%). Conclusions: Pyogenic granuloma was the most common gingival lesion. Squamous cell carcinoma was the only malignant lesion in which histologic examination was the definitive diagnostic measure. This study provides information about the frequencies and distributions of gingival lesions over 20 years.
- Intensity output and effectiveness of light curing units in dental offices(2018) Omidi, Baharan-Ranjbar; Gosili, Armin; Jaber-Ansari, Mona; Mahdkhah, AilinBackground: The aims of the study were measuring the light intensity of light curing units used in Qazvin?s dental offices, determining the relationship between the clinical age of these units and their light intensity, and identifying the reasons for repairing them. Material and Methods: In this cross-sectional study, the output intensity of 95 light curing devices was evaluated using a radiometer. The average output intensity was divided up into four categories (less than 200, 200-299, 300- 500, and more than 500 mW/cm 2 ). In addition, a questionnaire was designed to obtain information mainly about the type, clinical age, and frequency of maintenance of the units and the reasons for fixing them. Data were analyzed using Kolmogorov-Smirnov, chi-squared, and t-tests ( p < 0.05) on SPSS 24. Results: A total of 95 light curing units were examined, with 61 (64.2%) of them being of the LED type and 34 (35.8%) of the QTH type. While average light intensity in LED units was significantly higher than in QTH devices, the two device types were not significantly different regarding desirable light intensity (i.e., ? 300 mw/cm 2 ). A negative correlation was observed between clinical age and light intensity. In addition, bulb replacement in QTH devices was over three times as much as in LED units. Also, repairing QTHs was more than twice as much frequent as fixing LEDs. The most common reason for repair was the breakage of the tip of the device. Conclusions: The light intensity of LED units is significantly higher than that of QTH devices, and the frequency of repairing in QTHs was significantly more than in LEDs. Furthermore, light intensity decreases with aging, and dentists should regularly monitor the conditions of light units
- Influence of the dental prosthetic status on self-perceptions of health and treatment needs : a cross-sectional study of middle-aged adults with chronic disease(2018) Maia, Fabiana-Barros-Marinho; Tavares-de-Sousa, Emerson; de Sousa, Jossaria-Pereira; Scudine, Kelly-Guedes-de Oliveira; Freitas, Cláudia Helena Soares de; Sampaio, Fábio Correia; Forte, Franklin-Delano-SoaresBackground: Subjective aspects of dental prosthesis need in middle-aged adults are poorly explored, especially when the population presents chronic diseases. Objectives: To investigate if the use and necessity of dental prosthesis influence the self-perceptions of health and dental treatment need in middle-aged adults with chronic diseases. Material and Methods: A cross-sectional study was performed in 210 middle-aged adults. Socio-demographic aspects, dental services use, oral and general perceptions of health, dental treatment need and OIDP were assessed using a standardized questionnaire. One trained dentist evaluated the use and necessity of dental prosthesis. Data were analyzed using Chi-square and multivariate logistic regression ( p <0.05). Results: The use of dental prosthesis showed a proportion of 2.2:1 for upper to lower arch. Dental prosthesis need was largely prevalent (90 and 95% in upper and lower arch, respectively). The self-perceptions of dental treatment need and oral health were associated with the use and necessity of dental prosthesis ( p <0.05), which could not be observed in relation to the general self-perception. The adjusted model demonstrated that the subjective necessity of dental treatment was 16.04 (1.92-133.7) fold higher in individuals with necessity of rehabilitation in the lower arch. Besides, a positive self-perception of oral health (satisfied) was 2.59 (1.38-4.85) more expressive in individuals that used a dental prosthesis in upper arch. Conclusions: The self-perception of oral health was influenced by the use of maxillary dental prosthesis in individuals with chronic disease. Moreover, individuals were more likely able to perceive treatment need when the lower jaw was affected by tooth loss.
- Satisfaction in complete denture wearers with and without adhesives : a randomized, crossover, double-blind clinical trial(2018) Torres-Sanchez, Carlos; Montoya Salazar, Vanessa; Torres Lagares, Daniel; Gutiérrez Pérez, José Luis; Jiménez-Castellanos, EmilioBackground: The purpose of this study was to compare the satisfaction of patients regarding retention, stability and accumulation of particles with a randomized, double-blind crossed method in users with complete dentures with and without adhesive. Material and Methods: Seventeen edentulous individuals were randomized and received new upper and lower complete dentures. After a period of adaptation, they participated in some masticatory tests and clinical revisions, after use the protheses with and without the use of two denture adhesives: Adhesive A (Fittydent, Fittydent International GmbH) and adhesive B (Corega, GlaxoSmithKline) at 0, 7 and 14 days. Satisfaction was measured immediately after each test through a survey using a VAS scale (0-10) and data were analyzed with McNemar?s test with Bonferroni correction. Results: The results showed significant differences ( p <.01) between the study groups with adhesive A - B and the group without adhesive, but no significant differences were found between the two stickers for any of the variables studied. Conclusions: Complete denture adhesives significantly improved the satisfaction of patients because a better retention, stability and less accumulation of particles of the food substitute between the denture and the mucosa is obtained compared with non-use of complete denture adhesives.
- Bacterial adhesion on fissure sealants : effects of exposure to acidic drink(2018) Colombo, Marco; Dagna, Alberto; Molino, Domenico; Poggio, Claudio; Maiolatesi, Diego; Pietrocola, GiampieroBackground: Adherence of bacteria to teeth surface is considered an important step in the development of caries and the use of fissure sealants is crucial for the prevention of caries in occlusal surfaces of molars and premolars. The aim of this study was to investigate and compare the adherence of Streptococcus mutans to different fissure sealants, after acidic drink exposure. Material and Methods: The tested materials were Fissurit, Fissurit FX, Grandio Seal, Fuji Triage, Constic. Bacterial suspension was deposited onto each material and the adhesion was evaluated trough the colony forming units (CFUs) determination with or without acidic drink exposure. Results: The tested materials showed different behaviors with significant differences. Bacterial adherence values of the untreated materials were very dissimilar: Fuji Triage and Constic materials showed the better results ( P <0.05). Conclusions: Surface alteration after acidic drink exposure, changed the bacterial adhesion (except for Grandio Seal): Fissurit, Fissurit FX and Fuji Triage decreased their susceptibility to be colonized by S. mutans ( P <0.05); on the contrary, Constic increased up to ~4 times the bacterial adhesiveness respected to the untreated control ( P <0.05)
- A swift, easy and cheap protocol to evaluate the tooth bleaching in vitro(2018) Penha, Klayann-Varejão-de Freitas; Sousa, Anne-Carolyne-Santos; Oliveira, Camila-Araújo; de Andrade, Raissa-Silva-Bacelar; Vasconcelos, Daniel Fernando PereiraBackground: This study aims to develop a protocol that optimizes in vitro dental bleaching procedures in a cheap, fast and accessible manner. Material and Methods: 18 bovine incisors were cut and polished in enamel/dentin and submitted to staining in coffee solution during 72 hours. After the standardization and staining of the enamel surfaces, three groups (n = 6) were formed to receive three different gels, WHITENESS (commercial gel); H 2 O 2 - 5% (manipulated gel); CAR - BOPOL GEL (manipulated gel and without H 2 O 2 ). The color of the enamel surfaces was evaluated using digital images, obtained with digital camera and controlled luminosity, before and after staining, as well as after each bleaching step. Results: The average bleaching after 48 hours of procedure was: WHITENESS with 13.6 (± 1.2); H 2 O 2 (5%) with 9.8 (± 1.4) and CARBOPOL GEL with 2.9 (± 0.6). After 72 hours, WHITENESS presented a mean of 15.8 (± 0.7), the H 2 O 2 group (5%) 14.4 (± 1.5) and CARBOPOL GEL 4.6 (± 1.0). After completing 96 hours of whitening, WHI - TENESS presented an average of 18.3 (± 0.8), H 2 O 2 (5%) 16.7 (± 1.4) and CARBOPOL GEL 7.3 (± 0.8). Our data demonstrated that the protocol development for us can be used to evaluate dental bleaching in a short time, with 96 hours already was possible to detect significant differences, when compared with the longer times of experimental dental bleaching. Conclusions: The proposed protocol guarantees statistically significant results in 96 hours, confirming the efficacy, cheapness, viability and practicality of the protocol developed in this study.
- Titanium dioxide in dental enamel as a trace element and its variation with bleaching(2018) Vargas-Koudriavtsev, Tatiana; Duran-Sedo, Randall; Herrera-Sancho, O.A.Background: Titanium is a less studied trace element in dental enamel. Literature relates an increased Titanium concentration with a decreased enamel crystal domain size, which in turn is related to a higher color value. The aim of our study was to analyze the effect of tooth bleaching agents on its concentration in dental enamel by means of confocal Raman spectroscopy. Material and Methods: Human teeth were randomly distributed in six experimental groups (n=10) and submitted to different bleaching protocols according to the manufacturer ?s instructions. Confocal Raman spectroscopy was carried out in order to identify and quantify the presence of titanium dioxide molecules in enamel prior to and during whitening. Statistical analysis included repeated measures analysis of variance ( p ?0.05) and Bonferroni pairwise comparisons. Results: Titanium dioxide concentration was negatively affected by the longer bleaching protocols (at-home bleaching gels). All in-office whitening products increased significantly the studied molecule ( p ?0,05). Conclusions: All dental specimens depicted the presence of titanium dioxide as a trace element in dental enamel. Bleaching gels that have to be applied at higher concentrations but for shorter periods of time increase the concentration of titanium dioxide, whilst at-home whitening gels used for longer periods of time despite the lower concentration caused a loss in titanium.
- Calcifying odontogenic cyst : a 26-year retrospective clinicopathological analysis and immunohistochemical study(2018) Arruda, José A.; Silva, Leni-Verônica; Silva, Leorik-Pereira da; Monteiro, João-Luiz; Alvares, Pâmella; Da Silveira, Márcia María Fonseca; Sobral, Ana-PaulaBackground: To identify the prevalence and clinicopathological profile of calcifying odontogenic cysts (COC) stored at an oral pathology service, and to analyze the immunoexpression of cyclooxygenase 2 (COX-2) and cyclin D1 (CD1) in these cysts. Material and Methods: After a retrospective analysis (1990-2016) carried out to identify cases of COC, a sample of 12 cases was selected for immunohistochemical analysis of COX-2 and CD1 by the immunoperoxidase technique. Protein expression was evaluated semiquantitatively by attributing a score of 0 to 3 (0 = no staining; 1 = 1-25%; 2 = 26-50%, and 3 = >51% immunopositive cells). Results: Twenty cases of COC were diagnosed over the study period. These cysts were more common in the posterior mandible and in men (male-to-female ratio of 1.2:1), with a mean age of 29.9 years. Among the 12 cases analyzed, immunoexpression of COX-2 was observed only in the inflammatory infiltrate in 50% of the cysts (n = 6). Protein CD1 was detected (score 1) in 66.6% of cases (n = 8), and COX-2 was negative in 50% (n = 6). Conclusions: The prevalence of COC among all odontogenic cysts was 3.5%, representing an uncommon lesion. Immunohistochemical analysis suggested that COX-2 does not participate in lesion progression. The cell proliferation index of COC was low, as demonstrated by the expression of CD1, suggesting a proliferative profile compatible with more indolent lesions
- Interfacial fracture toughness of universal adhesive systems treated with an antioxidant(2018) Samimi, Pouran; Nazem, Reihaneh; Shirban, Farinaz; Khoroushi, MaryamBackground: Secondary caries, degradation of the dentin-resin interface and fracture of the restoration are the most common forms of failure. The aim of this study was to assess the interfacial fracture toughness of three different adhesive approaches and to compare their fracture toughness after surface treatment with antioxidant. Material and Methods: Seventy two dentin blocks with 3×4mm dimension and 3mm thickness were prepared and attached to precured 3×4×12mm composite blocks from both sides. Six adhesive groups (N=12), All-bond universal, Scotchbond universal and Clearfil SE bond with or without antioxidant treatment (Sodium Ascorbate 10% )were applied to dentin surfaces, a 160? polyethylene paper formed the chevron in adhesive-dentin interfaces. Chevron-notched beam fracture toughness was measured following a modified ISO 24370 standard. The uniform composite-dentin-composite block was subjected to a 4-point test in universal machine. Data were analyzed by Kruskal-Wallis, Wilcoxon signed-rank and Mann-Whitney tests (? =0.05). Results: Different adhesive approaches yielded different significant in fracture toughness rates. A significant increase of fracture toughness was observed between adhesive groups after antioxidant surface treatment. The difference in fracture toughness between Scotchbond universal and All-bond universal were significant. Conclusions: The highest value of fracture toughness was reported for Clearfil SE bond and the lowest value was found for All-bond universal. Sodium ascorbate as antioxidant surface treatment had a significant effect in increasing the fracture toughness.
- The effect of different force magnitudes for placement of orthodontic brackets on shear bond strength, in three adhesive systems(2018) Mohammadi, Amir; Pourkhamneh, Sohrab; Sadrhaghighi, Amir-HoumanBackground: Amount of pressure exerting on orthodontic brackets during bonding can create different thickness of adhesive and affect shear bonding strength(SBS) in different adhesive systems. The purpose of this study was to evaluate the effect of different force magnitudes for placement of brackets on SBS. Material and Methods: In an in vitro study, 420 brackets were placed on the bovine teeth, using three types of adhesives, Concise (chemically cured two-paste mix), Unite (chemically cured no mix), and Transbond XT( light cured), with the application of seven force magnitudes of 50, 100, 200, 300, 400, 600 and 1000 grams in twenty-one groups of twenty samples each. SBS means (using two-way ANOVA with Tukey?s post-hoc test) and adhesive remnant index were compared between these twenty-one groups. Results: SBS increased with an increase in force. No increase in Transbond XT SBS happened after 400 grams. In addition, Transbond XT had the lowest bond strength among three adhesives ( p <0.001). Adhesive remnant index (ARI) results also indicated a shift in the failure mode from bracket-adhesive interface to adhesive-enamel interface, as the bonding force got heavier ( p <0.05). Conclusions: The force applied on bracket during bonding influences the SBS. In order to have higher bond strength, application of heavy force would be advisable. It is also recommended that constant forces be applied for bracket bonding in future studies.
- Repair bond strength of composite : effect of surface treatment and type of composite(2018) Ghavam, Maryam; Naeemi, Maryam; Hashemikamangar, Sedighe Sadat; Ebrahimi, Hooman; KharaziFard, Mohammad J.Background: By an increase in use of composite restorations, some defects are also seen in these restorations, which need to be repaired. Since complete replacement of an old restoration may compromise the tooth structure, repair of defect is a more practical approach if there is no caries recurrence. Risk of pulp injury also decreases as such. One major challenge in restoration repair is to obtain a durable bond between the new and old composite. Laser irradiation has been suggested for surface preparation of old composite. This study aimed to assess the effect of composite surface preparation with Er,Cr:YSGG laser on microtensile bond strength to new composite. Material and Methods: A total of 18 blocks were fabricated in three groups of nanohybrid, microhybrid and Beautiful II giomer measuring 4x7x7 mm and subjected to 10,000 thermal cycles between 5-55°C with 30 seconds of dwell time. The samples were randomly assigned to no surface treatment (etching and bonding) or laser plus etching and bonding groups. Composite cylinders measuring 4x7x7 mm were fabricated of Beautiful, nanohybrid and microhybrid composites on old composite surfaces and subjected to 500 thermal cycles for 50 seconds between 5-55°C with 30 seconds of dwell time. Each block was sectioned into 10 samples and they were subjected to microtensile bond strength test. Data were analyzed using ANOVA and Tukey?s test. Results: In all composites, the mean bond strength in laser subgroups was higher than that in control subgroups except for giomer, which showed lower bond strength in laser subgroup. The lowest mean bond strength was noted in repair of Z350XT with Z350XT when the surface of old composite was etched (10.92 MPa). The highest mean bond strength was noted in repair of Z250 with giomer when the old composite surface was irradiated with laser (30.55 MPa). Conclusions: Er,Cr:YSGG laser plus etching increased the bond strength in all groups except for giomer group, which showed a reduction in bond strength.
