Degradation in the fatigue strength of dentin by cutting, etching and adhesive bonding (original) (raw)
Related papers
Egyptian dental journal, 2018
Aim: To investigate the effect of four different cutting tools on the adaptation of resin composite to enamel. Materials and methods: Twenty extracted sound human premolar teeth were used. Occlusal surfaces were ground flat and four random groups were formed according to the received surface treatment as follow, 600-grit silicon-carbide paper (control), carbide-bur, diamond-stone and air abrasion. Two successive layers of self-etch bonding agent were applied followed by composite build-up. Teeth were sectioned longitudinally, the interface between composite and enamel was examined by SEM and micrographs were obtained. Results: the best adaptation and least surface roughness were seen in the control group while the roughest surface was observed in the air abrasion group with presence of scanty microgaps.
Evaluation of enamel loss with bonding and debonding: A study with profile projector
Journal of Indian Orthodontic Society
Introduction: Accidental detachment of brackets is a common problem in orthodontic bonding and removal of the residual resin certainly results in some amount of enamel loss. Aims: The present study was undertaken to measure and compare the amount of enamel loss with different prophylactic methods and to check which method results in the least amount of enamel loss. Materials and Methods: One hundred and twenty human premolars extracted for orthodontic treatment purpose were included in the study and divided into three groups of forty samples each: Group 1 (tungsten carbide bur), Group 2 (diamond bur), and Group 3 (soflex disc). The groups were further subdivided into subgroups (a and b) of twenty samples each for different etching times. The enamel loss was measured with profile projector. Results: The mean enamel loss for different subgroups was as follows-subgroup 1a tungsten carbide bur with etching time of 20 s = 69.06 µm and subgroup 1b tungsten carbide bur with etching time of 40 s = 70 µm, subgroup 2a diamond bur with etching time of 20 s = 76 µm and subgroup 2b diamond bur with etching time of 40 s = 76.12 µm, and subgroup 3a soflex disc with etching time of 20 s = 68.32 µm and subgroup 3b soflex disc with etching time of 40 s = 72.24 µm. Statistical Analysis: Analysis of variance showed a significant difference (P < 0.05) in mean enamel loss between three prophylactic methods using different etching times. Unpaired t-test showed no significant difference in mean enamel loss between 20 and 40 s of etching time within groups. Conclusion: It is concluded that tungsten carbide bur resulted in the least amount of enamel loss and gouging and scarring is minimum when viewed with naked eye.
Effect of Different Dentin Treatment Protocols on Surface Roughness and Composite Bonding
Alexandria Dental Journal, 2020
INTRODUCTION: With advances in technology, other options besides the traditional cavity preparation with diamond and carbide burs have emerged; among them are laser and sono-abrasive systems. OBJECTIVES: The aim of this study was to compare in vitro the effect of (Er:YAG) laser with different radiation distances, sono-abrasion and rotary cutting on the surface roughness of dentin and the shear bond strength of resin composite to dentin using self-etching adhesive system. MATERIALS AND METHODS: 50 extracted human molars were randomly divided into 5 groups (n=10) received the following treatments. Group 1: carbide bur, Group 2: diamond bur, Group 3: sono-abrasion, Group 4: contact Er:YAG laser, Group 5: non-contact Er:YAG laser. Average surface roughness (Ra) was determined with a profilometer. Specimens in all groups were treated with self-etching adhesive system and composite build ups were done with Filtek Z-250. Bonding of resin composites to the dentine specimens was tested in shear mode. For morphological analysis; two extra teeth from each group were examined using a scanning electron microscope (SEM). RESULTS: The shear bond strength of composite to the laser irradiated dentine (contact and non-contact) ranged from 6.64 ± 5.24 MPa and 6.29 ± 2.08 MPa respectively, and were significantly lower than the bond strength seen in other groups. However, the surface roughness of the laser irradiated dentine was significantly higher than that of the sono-abraded dentine and bur-cut dentine. SEM revealed that, the dentine surfaces irradiated by laser showed a scaly and rugged appearance and open dentinal tubules without smear layer production. CONCLUSIONS: It was concluded that Er:YAG laser treatment reduced shear bond strength of resin composite to dentin in comparison with conventional treatment with high speed rotary and treatment with sono-abrasion. Different Er:YAG laser distance irradiations did not influence the shear bond strength of composite to dentin.
Adaptation of Resin Composite to Enamel Surface Prepared by Different Cutting Tools-Sem Study
2020
Aim: To investigate the effect of four different cutting tools on the adaptation of resin composite to enamel. Materials and methods: Twenty extracted sound human premolar teeth were used. Occlusal surfaces were ground flat and four random groups were formed according to the received surface treatment as follow, 600-grit silicon-carbide paper (control), carbide-bur, diamond-stone and air abrasion. Two successive layers of self-etch bonding agent were applied followed by composite build-up. Teeth were sectioned longitudinally, the interface between composite and enamel was examined by SEM and micrographs were obtained. Results: the best adaptation and least surface roughness were seen in the control group while the roughest surface was observed in the air abrasion group with presence of scanty microgaps.
Journal of Oral Research, 2020
Objective: This study investigated the effect of endogenous erosion on the microhardness of dentine and a nanofilled composite resin. Procedures for preventing erosion were also studied. Materials and Methods: 90 bovine dentine specimens were divided into three groups in accordance with the method for preventing: negative control, topical application of fluoride and resin-modified glass ionomer varnish. 120 composite resin specimens were distributed into four groups, which also included a resin sealant, among the preventive procedures. Specimens were then randomly divided into three sub-groups according to the exposure to simulate gastric acid solution and subsequent remineralization: negative control, 9 and 18 cycles. Surface analysis was carried out by measuring the Knoop hardness. The data obtained were statistically analyzed using 2-way ANOVA and Tukey test. Result: The mean hardness of dentine and of the composite specimens resin exhibited lower hardness after 18 cycles. Howeve...
Journal of Clinical and Experimental Dentistry, 2014
Objectives: To evaluate the effect of cutting teeth with different types of burs at various speeds on surface topography of tooth surface and interfacial gap formation at resin-tooth interface. Material and Methods: The human molars were divided into seven groups: Diamond bur in airrotor (DA) & micromotor (DM), crosscut carbide bur in airrotor (CCA) & micromotor (CCM), plain carbide bur in airrotor (CA) & micromotor (CM) and #600-grit silicon carbide paper (SiC). In five samples from each group Class II box-only cavities were restored. The occlusal surface of four teeth per group was flattened. Two out of four teeth were acid etched. Teeth were subjected for scanning electron microscopy (SEM). Results: Interfacial gap was observed in all groups with no significant difference. SEM observations revealed CA, CCA & DA were coarser than CM, CCM, DM and SiC. SEM of etched tooth surfaces revealed complete removal of amorphous smear layer in CA & CM, partial removal in CCA, CCM, DA & DM and no removal in SiC. Conclusions: Selecting an appropriate bur and its speed may not play an important role in bonding in terms of interfacial gap formation. Variable changes were observed in surface topography with different burs before and after acid etching.
Acta Scientific Dental Scienecs
Hardness is an important mechanical property, which has to be ascertained for the dental materials to ensure longevity of restorations placed in the mouth. Technically it is evaluated by making surface indentations and calculating the resistance offered by the material. Many time-tested tests are available to assess hardness. Such engineering tests are modified to the oral situations. An overview of hardness testing is given in this article.
Enamel cracks evaluation -A method to predict tooth surface damage during the debonding
Dental materials journal, 2015
The objective of this in vitro study was to evaluate the effect of the enamel cracks on the tooth damage during the debonding. Measurements of the cracks characteristics (visibility, direction, length, and location) were performed utilizing a scanning electron microscopy (SEM) technique and mathematically derived formulas (x=h/30, l=n*x) before and following the removal of mechanically retained metal and ceramic brackets. The likelihood of having greater extent enamel defects was higher for the teeth with pronounced cracks (odds vatios, OR=3.728), increased when the crack was located in more than one zone of the tooth (OR=1.998), and the inclination did not exceed 30-45° (OR=0.505). Using ceramic brackets the risk of greater amount tooth structure defects raised 1.45 times (OR=1.450). Enamel crack showing all these characteristics at the beginning of the orthodontic treatment and the use of ceramic brackets might predispose to higher risk of greater extent tooth surface damage after...
Effect of bur type and conditioning on the surface and interface of dentine
Journal of Oral Rehabilitation, 2005
The purpose of this in vitro study was to evaluate the surface and resin-dentine interface characteristics of permanent tooth dentine cut with diamond or carbide burs and treated with phosphoric acid (PA) or an acidic conditioner. Labial surfaces of permanent incisors were prepared into dentine with high-speed carbide or diamond burs and divided into two halves. Phosphoric acid 36% was applied on one half and non-rinse conditioner (NRC) was applied on the other half. Ten randomly selected scanning electron microscopy (SEM) fields from each specimen (n = 15) were evaluated. Occlusal surfaces of third molars were divided in two halves for evaluation of the resin-dentine interface. The halves were randomly assigned to one of each conditioner and restored with Prime & Bond NT/Spectrum. Ten specimens were analysed by SEM to evaluate hybrid layer formation and interfacial seal. We observed that surfaces prepared with carbide bur presented less residual smear plugs (P < 0AE05) than surfaces prepared with diamond burs. Surfaces conditioned with NRC, which is a smear layer modifier, presented more residual smear plugs than surfaces conditioned with PA (P < 0AE05). Treatment with PA resulted in more sealed interfaces than specimens treated with NRC.Within the limitations of this study the results showed that carbide burs leave a surface that is more conducive to bonding than diamond burs.