CONTACT ANGLE MEASUREMENT OF DENTAL RESTORATIVE MATERIALS BY DROP PROFILE IMAGE ANALYSIS

The capability of initial microbial adhesion to dental restorative composites surface is influenced by the surface wettability of the materials. The common method to evaluate surface wettability of materials is contact angle measurement. The existing conventional method to measure contact angle is by means of a contact angle (CA)-Goniometer device, which is less practically applicable in clinical circumstances. Therefore, a more practical and applicable method is needed to measure contact angle in clinical circumstances. This research was performed to compare between contact angles measured by means of a CA-Goniometer device and a new practical method of drop profile image analysis. In addition, since there were two different formulas that can be used to calculate contact angle value from a drop profile image, then we also need to evaluate which formula is more reliable to be used. Tests were carried out using three composite discs (Clearfill-Kuraray Medical, Inc.) sample and deionised water for different measurement procedures. One drop of 3µl liquid was dropped onto the surface of the composite discs, and the drop profile image was captured by means of a customized home-made device connected to a digital camera. Two different formulas were used to calculate the contact angle value from the drop profile image, namely the “linier gradient equation” and the “tangential line”. The contact angle values obtained from the two different formulas were compared with the value obtained from the conventional method descriptively. Tests were carried out using three composite discs (Clearfill-Kuraray Medical, Inc.) sample and deionised water for different measurement procedures. One drop of 3µl liquid was dropped onto the surface of the composite discs, and the drop profile image was captured by means of a customized home-made device connected to a digital camera. Two different formulas were used to calculate the contact angle value from the drop profile image, namely the “linier gradient equation” and the “tangential line”. The contact angle values obtained from the two different formulas were compared with the value obtained from the conventional method descriptively. The differences in percentage between the contact angle value calculated by the “linier gradient equation” and “tangential line” formulas, and those calculated by means of the CA-Goniometer are 20,56% and 3,51%, respectively. It is obviously demonstrated that the value obtained by the “tangential line” formula has a smaller difference compared to those obtained by the “linier equation gradient” formula. Among the two different formulas, it is confirmed that the contact angle value calculated with the “tangential line” formula has closer similarity with the value obtained from the CA-Goniometer. This result confirms that the new practical method of drop profile image analysis is promising for measuring contact angle values in clinical circumstances. Related to the drop profile image analysis, the “tangential line” formula is more accurate compared to the “linier gradient equation” formula

Peranan Transforming Growth Factors- Beta (Tgf- 3) Dalam Pembentukan Dentin Tersier (Telaah Pustaka

ABSTRAK Jaringan dentin dan pulpa mengalami perubahan clan kerusakan karena pengaruh linatingan sepanjang kehidupan manusia. Terkena jejas, set-sel pulpa rnernpunyai kernampuan untuk memperhaiki dirt dan menyusun matriks dentin tersier pada daerah jejas. Transforming Growth Factors-Beta {TGF- 1i) rnerupakan salah satu faktor perturribunan yang secara Walt mengalur rangkaian peristiwa moickuler maupun setuler pada pembentukan dentin tersier. Studi literatur ini bertujuan untuk rnemaparkan pengaruh TGF- f3 pada pernbentukan dentin tersier. Selama terjadi jejas, odontobtas akan tedokalisasi pada daerah yang mengalami kerusakan dan menaikkan regulasi aktivitas sckresi dentin. Jejas yang lebin parah dapat rnengakibatkan kematian odontoblas. Sel-set ini akan digantikart oleh populasi odonfoblastlike cell, yang berdiferensiasi dart set progenitor pulpa dan mensekresi matriks dentin. TGF- yang terda pat didalam matriks dentin menyediakan somber endogen dart cell-signalling molecules untuk menslimuli dentinogenesis reaksioner maupun reparalif setelah terjadinya jejas pada gigi. Kata kunci: TGF- /3, dentin reaksioner, dentin reparatif, dentinogenesi

Immediate repair bond strengths of microhybrid, nanohybrid and nanofilled composites after different surface treatments

OBJECTIVES: To evaluate immediate repair bond strengths and failure types of resin composites with and without surface conditioning and characterize the interacting composite surfaces by their surface composition and roughness. METHODS: Microhybrid, nanohybrid and nanofilled resin composites were photo-polymerized and assigned to four groups: (1) no conditioning (Control), (2) no conditioning, polymerized against a Mylar strip (Control, with strip), (3) intermediate adhesive resin (IAR) application, and (4) chair-side silica coating, silanization and intermediate resin application (SC). Resin composites, similar as their substrates, were adhered onto the substrates. Shear force was applied to the interface in a universal testing machine and failure types were evaluated under light microscopy. Surface characterization was done by contact angle measurements, X-ray photoelectron spectroscopy, scanning electron and atomic force microscopy. RESULTS: Significant effects of the resin composite type and surface conditioning were observed. Conditioning the composites with their IARs does not result in significant improvements in bond strength compared to the control with strip (bond strengths between 14.5 and 20.0 MPa). SC increased the bond strength in all composites except TE by an average 8.9 MPa, while in all composites the surface roughness increased from 7 to 384 microm. Failure types in this group were exclusively cohesive. Physico-chemical modelling of the composite surfaces showed that the surfaces were dominated by the resin matrix, with a major increase in silica-coverage after SC for all composites. CONCLUSION: Intermediate adhesive resin conditioning did not improve the composite-to-composite immediate repair strength. Silica coating and silanization followed by its corresponding IAR, strongly increased repair bond strengths and provided exclusively cohesive failures in the substrate in all composites

PERBEDAAN RADIOPASITAS ANTARA SEALER BERBAHAN DASAR RESIN EPOKSI DAN SEALER BERBAHAN DASAR SENG OKSID EUGENOL DENGAN TEKNIK RADIOGRAFI PERIAPIKAL DIGITAL

Radiopacity is the inability of X-rays to penetrate material that causes radiopaque. Sealer, along with gutta percha, is used as a root canal filling material. Then, obturation process of the root canal treatment was evaluated by radiograph. Therefore, the sealer must be radiopaque to difference with anatomy structure in the radiograph. The aim of this study was to determine the difference of radiopacity between epoxy resin based sealer compared with zinc oxide eugenol based sealer on digital periapical radiography techniques. Twenty sealer study samples were divided into two groups. Group I consisted of 10 samples of epoxy resin based sealer . Group II consisted of 10 samples of zinc oxide eugenol based sealer. Images were taken from both groups by using radiograph technique with periapical digital radiographic techniques with the specification of 50 kVp, 7mA , and 0.8 seconds. Observations were carried out using the Image J software. The results of calculations were analyzed by using the Independent t - test. The results showed that significant radiopacity differences were occurred in both groups (p < 0.05). Epoxy resin based sealer (6,85 mmAl) was significantly more radiopaque than zinc oxide eugenol based sealer (3,22 mmAl). Radiopacity was influenced of chemical composition, inorganic contrast medium, atom number, and the density of the sealer. The conclusion of this study is that epoxy resin based sealer is more radiopaque than zinc oxide eugenol based sealer. Keywords: radiopacity, sealer, radiography, periapical, digital

Effect of biofilm on the repair bond strengths of composites

Composite restorations degrade during wear, but it is unknown how wear affects the composite surface and influences composite-to-composite bonding in minimally invasive repair. Here, it is hypothesized that in vitro exposure of composites to oral biofilm yields clinically relevant degradation of composite surfaces, and its influence on composite-to-composite bonding is determined. Biofilms on composite surfaces in vitro increased their roughness and decreased filler particle exposure, except for a microhybrid composite, similar to effects of clinical wear in palatal appliances. Failure shear stresses after intermediate-adhesive-resin application were significantly lower after aging by in vitro exposure to biofilms, while silica-coating maintained the same failure stress levels as in non-aged composites. Failure modes were predominantly cohesive after silica-coating, while intermediate-adhesive-resin application yielded more adhesive failure. It is concluded that in vitro exposure to oral biofilm is a clinically relevant aging condition, and that silica-coating is to be preferred for the repair of aged composites

Biofilm Formation on Dental Restorative and Implant Materials

Biomaterials for the restoration of oral function are prone to biofilm formation, affecting oral health. Oral bacteria adhere to hydrophobic and hydrophilic surfaces, but due to fluctuating shear, little biofilm accumulates on hydrophobic surfaces in vivo. More biofilm accumulates on rough than on smooth surfaces. Oral biofilms mostly consist of multiple bacterial strains, but Candida species are found on acrylic dentures. Biofilms on gold and amalgam in vivo are thick and fully covering, but barely viable. Biofilms on ceramics are thin and highly viable. Biofilms on composites and glass-ionomer cements cause surface deterioration, which enhances biofilm formation again. Residual monomer release from composites influences biofilm growth in vitro, but effects in vivo are less pronounced, probably due to the large volume of saliva into which compounds are released and its continuous refreshment. Similarly, conflicting results have been reported on effects of fluoride release from glass-ionomer cements. Finally, biomaterial-associated infection of implants and devices elsewhere in the body is compared with oral biofilm formation. Biomaterial modifications to discourage biofilm formation on implants and devices are critically discussed for possible applications in dentistry. It is concluded that, for dental applications, antimicrobial coatings killing bacteria upon contact are more promising than antimicrobial-releasing coatings

Influence of a proximal margin elevation technique on marginal adaptation of ceramic inlays

PURPOSE: Evaluating the effect of a proximal margin elevation technique on marginal adaptation of ceramic inlays. METHODS: Class II MOD-cavities were prepared in 40 human molars and randomly distributed to four groups (n = 10). In group EN (positive control) proximal margins were located in enamel, 1 mm above the cementoenamel junction, while 2 mm below in groups DE-1In, DE-2In and DE. The groups DE-1In, DE-2In and DE simulated subgingival location of the cervical margin. In group DE-1In one 3 mm and in group DE-2In two 1.5 mm composite layers (Tetric) were placed for margin elevation of the proximal cavities using Syntac classic as an adhesive. The proximal cavities of group DE remained untreated and served as a negative control. In all groups, ceramic inlays (Cerec 3D) were adhesively inserted. Replicas were taken before and after thermomechanical loading (1.200.000 cycles, 50/5°C, max. load 49 N). Marginal integrity (tooth-composite, composite-inlay) was evaluated with scanning electron microscopy (200×). Percentage of continuous margin (% of total proximal margin length) was compared between groups before and after cycling using ANOVA and Scheffé post-hoc test. RESULTS: After thermomechanical loading, no significant differences were observed between the different groups with respect to the interface composite-inlay and tooth-composite with margins in dentin. The interface tooth-composite in enamel of group EN was significantly better compared to group DE-2In, which was not different to the negative control group DE and DE-1In. CONCLUSION: Margin elevation technique by placement of a composite filling in the proximal box before insertion of a ceramic inlay results in marginal integrities not different from margins of ceramic inlays placed in dentin