Adhesion and whitening efficacy of P11-4 self-assembling peptide and HAP suspension after using NaOCl as a pre-treatment agent

Background This study evaluated the adhesion and whitening efficacy of a mixture of hydroxyapatite and P11-4 self-assembling peptide (HAP-peptide) on bovine enamel after pre-treatment with low-concentrated sodium hypochlorite (NaOCl). Methods Fifty-two caries-free bovine incisors were selected. 50 teeth were randomly allocated to five groups (n = 10). The first group was treated with a mixture of 6.25 wt% HAP and 5 ml P11-4 peptide, using NaOCl 3% as pre-treatment. Second, third and fourth groups were treated with 6.25 wt% HAP, 5 ml P11-4 peptide, and NaOCl 3%, respectively. In the fifth group, only water was applied (control group). The color of samples was measured using a spectrophotometer (USB4000-VIS-NIR-ES, Ostfildern, Germany). To evaluate color changes, ΔE values were statistically analyzed. Finally, adherence of HAP particles on two enamel surfaces with and without pre-treatment with NaOCl was analyzed with SEM. Results It was observed that the ΔE of the HAP-peptide suspension after pre-treatment with NaOCl was significantly stronger than the control group. In contrast, the overall color changes of separate applications of HAP, peptide, and NaOCl did not differ notably from the control group. SEM observations confirmed that pre-treatment with NaOCl resulted in a more pronounced coverage of HAP on the enamel surface. Conclusions Pre-treatment with a low-concentrated NaOCl enhanced the adherence of the HAP layer on the enamel surface, resulting in a stronger whitening effect

Tooth whitening with an experimental toothpaste containing hydroxyapatite nanoparticles

Background The aim of this study was to evaluate the postbrushing tooth-whitening effect of toothpaste containing hydroxyapatite nanoparticles (nano-HAPs). The impact of the concentration on the whitening performance of nano-HAP toothpaste was also investigated. Methods Two concentrations of nano-HAP (10 wt% and 1 wt%) were incorporated in nonabrasive toothpastes. Forty bovine incisors were randomly assigned into four groups: 10 wt% nano-HAP, 1 wt% nano-HAP, toothpaste without nano-HAP as a negative control and water as a blank control. Each tooth was treated with the toothpaste three times and hydrodynamic shear force (HSF) once. The teeth surfaces were observed by SEM after each application. Tooth color (L*, a* and b* values) was measured by a spectrophotometer, and color changes (△E, △L, △a and △b values) were calculated. Two-way mixed ANOVA was performed to evaluate the influence of the concentration and repeated application on the tooth-whitening effect of nano-HAP. Results We found that nano-HAP-treated enamel exhibited higher L* values and lower a* and b* values than the control groups (P < 0.05). The 10 wt% nano-HAP group showed significantly higher △E values than the 1 wt% nano-HAP group (P < 0.05). After three applications, the △E mean value of the 10 wt% nano-HAP group was 4.47. The △E and △L values were slightly reduced after HSF (P < 0.05). For both nano-HAP groups, HAP single crystallites and agglomerates were identified, and their sizes grew with nano-HAP reapplication. Conclusions In conclusion, nano-HAP toothpaste has a satisfying postbrushing whitening effect and good resistance to mechanical forces. The whitening effect seemed to be concentration-dependent

Adhesion and whitening effects of P11-4 self-assembling peptide and HAP suspension on bovine enamel

OBJECTIVES This study evaluated the adhesion and whitening effects of a combination of P11-4 self-assembling peptide and hydroxyapatite (peptide-HAP) on bovine enamel. METHODS Forty-six caries-free bovine teeth were selected, and 40 teeth were randomly allocated to one of five groups (n = 8). First, the effects of application frequency, exposure time, and storage in saliva on the whitening effects of an experimental low-concentrated peptide-HAP suspension (0.5 wt% HAP; Curodont, Credentis) were evaluated and compared with a commercial bleaching agent (VivaStyle Paint on Plus, VS, Ivoclar Vivadent). Tooth color was measured using a spectrophotometer (Gretag MacBeth), and color changes ΔE were statistically analyzed. Second, the effects of peptide-HAP concentration (low versus high: 6.25% HAP; Curodont Protect), and its interactions with saliva and postapplication restaining, were investigated. Third, enamel surfaces (n = 2) were treated with low concentration peptide-HAP and high-concentration peptide-HAP in polymeric and monomeric forms (Curodont Protect & Curodont Repair, Credentis) and analyzed by SEM. RESULTS The ΔE of the low-concentration peptide-HAP suspension did not differ from that of VS. Application frequency, exposure time, and storage in saliva did not have any significant impact on whitening efficacy of the peptide-HAP suspension. Increasing the concentration of the suspension did not promote overall ΔE. SEM observations confirmed the presence of the newly generated peptide and HAP on the enamel surface. CONCLUSIONS The peptide-HAP suspension is a mild tooth whitener, and the adhesion of peptide-HAP to enamel is concentration dependent. CLINICAL RELEVANCE This peptide-HAP suspension is effective in offsetting discoloration caused by restaining after treatment

Diagnostic validity of early proximal caries detection using near-infrared imaging technology on 3D range data of posterior teeth

OBJECTIVES This in vitro study analysed potential of early proximal caries detection using 3D range data of teeth consisting of near-infrared reflection images at 850~nm (NIRR). MATERIALS AND METHODS Two hundred fifty healthy and carious permanent human teeth were arranged pairwise, examined with bitewing radiography (BWR) and NIRR and validated with micro-computed tomography. NIRR findings were evaluated from buccal, lingual and occlusal (trilateral) views according to yes/no decisions about presence of caries. Reliability assessments included kappa statistics and revealed high agreement for both methods. Statistical analysis included cross tabulation and calculation of sensitivity, specificity and AUC. RESULTS Underestimation of caries was 24.8% for NIRR and 26.4% for BWR. Overestimation was 10.4% for occlusal NIRR and 0% for BWR. Trilateral NIRR had overall accuracy of 64.8%, overestimation of 15.6% and underestimation of 19.6%. NIRR and BWR showed high specificity and low sensitivity for proximal caries detection. CONCLUSIONS NIRR achieved diagnostic results comparable to BWR. Trilateral NIRR assessments overestimated presence of proximal caries, revealing stronger sensitivity for initial caries detection than BWR. CLINICAL RELEVANCE NIRR provided valid complement to BWR as diagnostic instrument. Investigation from multiple angles did not substantially improve proximal caries detection with NIRR

Shrinkage vectors in flowable bulk-fill and conventional composites: bulk versus incremental application

OBJECTIVES Sufficient depth of cure allows bulk-fill composites to be placed with a 4-mm thickness. This study investigated bulk versus incremental application methods by visualizing shrinkage vectors in flowable bulk-fill and conventional composites. MATERIALS AND METHODS Cylindrical cavities (diameter = 6 mm, depth = 4 mm) were prepared in 24 teeth and then etched and bonded with OptiBond FL (Kerr, Italy). The composites were mixed with 2 wt% radiolucent glass beads. In one group, smart dentin replacement (SDR, Dentsply) was applied in bulk "SDR-bulk" (n = 8). In two groups, SDR and Tetric EvoFlow (Ivoclar Vivadent) were applied in two 2-mm-thick increments: "SDR-incrementa" and "EvoFlow-incremental". Each material application was scanned with a micro-CT before and after light-curing (40 s, 1100 mW/cm2), and the shrinkage vectors were computed via image segmentation. Thereafter, linear polymerization shrinkage, shrinkage stress and gelation time were measured (n = 10). RESULTS The greatest shrinkage vectors were found in "SDR-bulk" and "SDR-increment2," and the smallest were found in "SDR-increment1-covered" and "EvoFlow-increment1-covered." Shrinkage away from and toward the cavity floor was greatest in “SDR-bulk“ and “EvoFlow-increment2", respectively. The mean values of the shrinkage vectors were significantly different between groups (one-way ANOVA, Tamhane's T2 test, p < 0.05). The linear polymerization shrinkage and shrinkage stress were greatest in Tetric EvoFlow, and the gelation time was greatest in "SDR-bulk". CONCLUSIONS The bulk application method had greater values of shrinkage vectors and a higher debonding tendency at the cavity floor. CLINICAL RELEVANCE Incremental application remains the gold standard of composite insertion

Influence of Powered Toothbrushes on Dentine Wear

Svrha: Svrha rada bila je odrediti stupanj trošenja dentina nakon što se zubi četkaju električnom četkicom s glavama različitih veličina te primijene različita opterećenja u usporedbi s običnom (mehaničkom) četkicom za zube. Materijal i postupci: Za to su odabrane električne četkice Sonicare-Elite s malom i standardnom veličinom glave i vertikalnim opterećenjem od 90 i 150 grama te mehanička četkica Oral-BP35 s vertikalnim opterećenjem od 150 grama. Ona je istodobno služila i kao kontrolna. Uređajem za simulaciju četkanja s različitim brojem okretaja koristili smo se kako bismo postigli abraziju dentina četkanjem. Za standardne veličine glave Sonicare-Elite rabilo se 12 000 okretaja, a za mini glavu 18 000. Za četkicu Oral-B-P35 izabrali smo 12 500 okretaja. Laserskim scannerom 3D koristili smo se za evaluacije trošenja dentina. Rezultati: Rezultati su pokazali da je najveće trošenje dentina bilo kod uporabe manualne četkice (107,26μm), a najmanje kod četkice Sonicare-Elite sa standardnom veličinom glave i 90 grama vertikalnog opterećenja (47.7μm). Nisu potvrđene statistički znatne razlike izmedju električne četkice s “mini” glavom (90 grama opterećenja) i standardnom veličinom glave (90 i 150 grama opterećenja) te električne četkice s “mini” glavom i opterećenjem od 150 grama i manualne četkice. Zaključak: Električne četkice s različitim veličinama glave i različitim vertikalnim opterećenjima različito troše dentin i što je manja glava te jače opterećenje, to je veće trošenje dentina.Purpose: The aim of this study was to evaluate the dentine wear after brushing with powered toothbrushes with different brush head size and different load applied in comparison with manual toothbrush. Material and Methods: Powered toothbrush Sonicare Elite with mini and standard size brush heads at 90g and 150g vertical load, and the manual toothbrush Oral-B-P35 with a vertical load of 150g, were used as a control group. Toothbrushing machine with different number of strokes was used for dentine abrasion assessment. For Sonicare-Elite with standard size head 12000 strokes was used, for Sonicare Elite with mini head 18000 and for manual toothbrush 12500 strokes. 3D-Laser scan was used for evaluation of dentine wear. The highest dentine wear was recorded using manual toothbrush (107.26μm), while the lowest using Sonicare-Elite with standard size head at 90g vertical load (47.7μm). Results: No statistical significance was found between powered toothbrushes with: mini head (90g load), standard head (90 and 150g load) and between mini head of powered toothbrushes at 150g vertical load and manual toothbrush. Conclusion: Powered toothbrushes with different brush head size and different load applied caused different tooth wear: the smaller the brush head and the higher the load is, the higher the dentine wear is

Attenuation of near-ultraviolet, visible and near-infrared light in sound and carious human enamel and dentin

Objectives This in vitro study aimed to investigate the optical attenuation of light at 405, 660 and 780 nm sent through sound and carious human enamel and dentin, including respective individual caries zones, as well as microscopically sound-appearing tissue close to a carious lesion. Materials and methods Collimated light transmission through sections of 1000-125-mu m thickness was measured and used to calculate the attenuation coefficient (AC). The data were statistically analysed with a MANOVA and Tukey's HSD. Precise definition of measurement points enabled separate analysis within the microstructure of lesions: the outer and inner halves of enamel (D1, D2), the translucent zone (TZ) within dentin lesions and its adjacent layers, the enamel side of the translucent zone (ESTZ) and the pulpal side of the translucent zone (PSTZ). Results The TZ could be distinguished from its adjacent layers and from caries-free dentin at 125 mu m. Sound-appearing dentin close to caries lesions significantly differed from caries-free dentin at 125 mu m. While sound and carious enamel exhibited a significant difference (p 0.05). At 405 nm, no difference was found between sound and carious dentin (p > 0.05). Conclusions Light optical means enable the distinction between sound and carious tissue and to identify the microstructure of dentin caries partially as well as the presence of tertiary dentin formation. Information on sample thickness is indispensable when interpreting the AC

The competition between enamel and dentin adhesion within a cavity: an in vitro evaluation of class V restorations

To gain more insight into the consequences of curing contraction within the tooth cavity, we assessed the margin behavior of 12 contemporary restorative systems in class V restorations with margins located on enamel and dentin after mechanical loading and water storage. Mixed class V cavities were prepared on extracted human molars and restored using five etch and rinse and seven self-etch adhesive systems with their corresponding composites. Marginal adaptation was evaluated by using a computer-assisted quantitative marginal analysis in a scanning electron microscope (SEM) on epoxy replicas before, after thermal and mechanical stressing and after 1 year of water storage. The interactions of "testing conditions", "adhesive-composite combination" and "tooth substrate" with "marginal adaptation" were evaluated by two-way ANOVA. Fatigue, stress and storage conditions had significant effects on the marginal adaptation. Only two groups (Optibond FL and G Bond) presented equal percentages of marginal adaptation on enamel and dentin; in the other groups, the rate of degradation was product dependent. All materials tested showed a distinct behavior on enamel and dentin. In addition to mechanical resistance and long-term stability, differences within materials also exist in their ability to simultaneously bond to enamel and dentin