Evaluation and comparison of the effect of incorporating zinc oxide and titanium dioxide nanoparticles on the bond strength and microleakage of two orthodontic fixed retainer adhesives.

BACKGROUND: An adhesive with both proper mechanical and antimicrobial properties seems to be beneficial. We aimed to investigate the effect of zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles (NPs) on bond strength and microleakage of two different fixed retainer adhesives. METHODS: In this in vitro experimental study, 168 extracted human incisors were randomly divided into six groups of 28 (eight double-tooth specimens for the bond strength test and 12 specimens for the microleakage test). In three groups: Transbond XT (3M Unitek, Monrovia, CA) without NPs, with 1% ZnO NPs and with 1% TiO2 NPs were applied. The other three groups included Ortho Connect Flow (GC orthodontics, Tokyo, Japan) composite with the same order to bond a 0.175-inch multistrand wire to the lingual surfaces of the teeth. The bond strength was measured using the Universal Testing Machine, and the adhesive remnant index was reported using a stereomicroscope (Nikon, SMZ800, Tokyo, Japan). The dye-penetration method was used to determine the microleakage. RESULTS: For bond strength, there was no significant difference among groups. For microleakage, there was no significant difference between GC and Transbond XT groups. However, in subgroups of Transbond XT, the addition of TiO2 NPs increased the microleakage significantly in comparison with ZnO and control groups (P = 0.011). There was no significant statistical difference between the groups in terms of residual adhesives (P = 0.166). CONCLUSIONS: Through the incorporation of 1% TiO2 and ZnO NPs into the fixed retainer adhesive, the bond strength was maintained within the clinically acceptable range. The addition of TiO2 NPs to Transbond XT significantly increased the percentage of microleakage.

Effect of nano-zinc oxide and nano-chitosan particles on the shear bond strength of dental composites used as orthodontic adhesive.

BACKGROUND: This study aimed to evaluate the effect of the combination of zinc oxide nanoparticles (NPs) and chitosan NPs on the shear bond strength (SBS) of composites used for orthodontic bonding. METHODS: Four groups of composites (n = 10), containing 0%, 1%, 5%, and 10% w/w NP fillers, respectively, were used to bond brackets to the surfaces of 40 intact bovine incisors. After 1000 rounds of thermal cycling at 5°C-55°C, all specimens were mounted in acrylic blocks. The SBS was tested using a universal testing machine, and the adhesive remnant index scores were registered using a stereomicroscope. Data were statistically analyzed using a 1-way ANOVA and the Kruskal-Wallis test. RESULTS: The highest value of mean SBS was found in the control group, and the lowest value was found in the group with composite containing 10% NPs. The adhesive remnant index did not differ significantly among the groups (P = 0.823). CONCLUSIONS: Incorporation of 1% and 5% zinc oxide and chitosan NPs had no effect on the SBS of composite, and the obtained SBS values were similar to that of the control group.

Effect of teledentistry on the oral health status of patients undergoing fixed orthodontic treatment at the first three follow-up visits.

BACKGROUND: As the prevalence of such oral diseases as dental caries and periodontal problems increases during fixed orthodontic treatment, patient education is an essential aspect of any such treatment. Two methods have been proposed for this purpose: direct education in a clinic (the conventional method); and education using social media, such as the Telegram application (a type of teledentistry). OBJECTIVES: The aim of this study was to evaluate the effect of teledentistry as an educational tool on the oral health status of patients undergoing fixed orthodontic treatment at the first 3 follow-up visits. MATERIAL AND METHODS: Sixty participants were enrolled from patients whose fixed orthodontic treatment was to begin at a dental clinic in Tehran, Iran. They were randomly assigned to one of 2 trial arms. At the end of the 1st appointment, one of the groups was educated in person about maintaining oral hygiene during treatment, and an educational clip was sent to the members of the other group via the Telegram application. During the next 3 follow-up appointments, plaque index (PI), bleeding on probing (BOP), and gingival color and consistency were analyzed for each patient to assess their oral hygiene compliance during treatment. RESULTS: There was a statistically significant difference in PI and BOP between the 2 groups at the 3rd and 4th appointments; however, gingival color and consistency did not differ significantly with regard to the manner of education (p > 0.05). Patient age did not have a considerable effect on the oral health status in either group (p > 0.05). CONCLUSIONS: Teledentistry is an effective and efficient method to improve oral hygiene in patients undergoing fixed orthodontic treatment.

Evaluation of the effect of antimicrobial nanoparticles on bond strength of orthodontic adhesives: A review article.

Background: Antimicrobial nanoparticles (NPs) have various applications in different fields of dentistry. The purpose of incorporating NPs into orthodontic adhesives is to inhibit the cariogenic bacteria and reduce decalcifications around bonded orthodontic brackets. However, they may affect the physical and mechanical properties of adhesive such as shear bond strength (SBS). This review was done to answer the question whether the incorporation of antimicrobial NPs into orthodontic adhesives changes the SBS. Materials and Methods: An electronic search was performed with keywords such as adhesives AND nanoparticles AND orthodontics AND shear strength. After screening and applying eligibility criteria, 18 relevant studies were included. Results: The pooled data suggest that except for 10 wt% of various NPs incorporation, there is no significant difference in SBS between control conventional adhesives and experimental modified ones with tested concentrations. Conclusion: The SBS of orthodontic adhesives containing up to 5% NPs is in clinical acceptable range. However, generalizing the results to in vivo situation may be problematic and further studies are required.

Comparison of intraoral digital radiography and cone-beam computed tomography in the measurement of periodontal bone defects.

BACKGROUND: Periodontal disease has a high prevalence in many countries. Thus, the early detection of periodontal disease is important in order to obtain the most appropriate treatment plan to prevent tooth loss, and subsequently, to maintain the patient's general health. OBJECTIVES: The aim of this study was to compare the accuracy of cone-beam computed tomography (CBCT) and intraoral parallel digital radiography in measuring the dimensions of periodontal bone defects. MATERIAL AND METHODS: In this in vitro study, 236 periodontal bone defects were artificially created in dry human mandibles using a burr. Defects included horizontal, one-, two-, and three-wall defects, craters, dehiscences, and fenestrations. Intraoral digital radiographs were obtained using the parallel technique with photostimulable phosphor plates (PSP) and CBCT scans were performed. Two calibrated observers evaluated the images and measured the dimensions of the defects. Clinical probing was performed and considered as the gold standard. The measurements of digital radiography and CBCT were compared to those achieved by probing to evaluate their accuracy. RESULTS: Cone-beam computed tomography had a significantly stronger correlation with the gold standard than intraoral parallel digital imaging. In the total assessment of the periodontal defects, the intraclass correlation coefficient (ICC) was calculated at 0.93 for CBCT-probe and at 0.78 for PSP-probe (p < 0.05). CONCLUSIONS: The accuracy of CBCT was superior to that of intraoral digital radiography for measuring horizontal, one-, two-, and three-wall defects, craters, dehiscences, and fenestrations.