Journal of oral science最新文献

Purpose: The aim of this study was to evaluate the effects of apical backfilling depth on the apical sealing of different root canal filling qualities and morphologies.

Methods: 3D-printed root canals (A: round, B: oval, C: long oval, D: flat) were used and divided into subgroups by root canal filling quality (a: good, b: poor, c: nonfilling) and backfilling depth (3 mm, 5 mm). A glucose microleakage device was used to measure leakage.

Results: (1) 3-mm iRoot BP Plus was filled at the apex, and no obvious leakage occurred in the good root canal filling group, which was significantly smaller than that in the poor/nonfilling groups (P < 0.05). Under good root canal filling conditions in groups A, B, C, and D, no obvious leakage was observed. Under poor/nonfilling root canal filling conditions, there was significant leakage; A and B (P > 0.05) and C and D were compared (P < 0.05). (2) Apical backfilling with 5-mm iRoot BP Plus showed no significant leakage in the poor root canal filling groups with the four morphologies.

Conclusion: 3-mm iRoot BP Plus was filled at the apex, root canal filling was poor, apical sealing was poor, and root canal morphology affected apical sealing. Apical backfilling with 5-mm iRoot BP Plus improved apical sealing under poor root canal filling conditions, and apical sealing was unaffected by root canal morphology.

Sclerosing odontogenic carcinoma (SOC) is a very rare malignant odontogenic tumor characterized by sclerotic stroma and single-file cord-like tumor cell structures. A 38-year-old man presented with extraoral swelling and right mental region paralysis. Panoramic radiography revealed an ill-defined radiolucent lesion extending from the right mandibular ramus to the right lower canine. Magnetic resonance imaging showed tumor invasion into the right inferior alveolar nerve and masseter muscle. Hemimandibulectomy, bilateral neck dissection, and mandibular reconstruction were performed using a rectus abdominis musculocutaneous flap and a titanium plate. Histopathology and immunohistochemistry confirmed SOC diagnosis. No recurrence occurred in the 1-year follow-up. In this paper, a case of SOC with a high Ki-67 labeling index was reported. Since SOC is prone to nerve invasion, treatment is resection with an appropriate surgical margin.

Purpose: To investigate the bactericidal and biofilm removal effect of super reducing water (SRW) on Streptococcus mutans (S. mutans) adhered to orthodontic brackets, in vitro.

Methods: Three types of brackets were bonded to aluminum disks. After the formation of S. mutans biofilms on the surfaces, the brackets were divided into three groups (n = 44 each) based on their exposure to SRW: group 1, no treatment; group 2, treated for 5 min; and group 3, treated for 10 min. Total viable counts, adenosine triphosphate measurements, crystal violet assay, and scanning electron microscopy were used to evaluate the effect of SRW.

Results: The bacterial counts in groups 2 and 3 were significantly lower than those in group 1 (P < 0.001); however, no significant differences were observed between groups 2 and 3. Marked decreases in the number of bacterial colonies and extent of biofilm formation were observed in groups 2 and 3 compared to group 1. No significant differences in the number of bacterial colonies and amount of biofilm were observed among the three types of brackets in each group.

Conclusion: These findings indicate the bactericidal and biofilm removal effect of SRW treatment on S. mutans adhered to orthodontic brackets.

Purpose: The purpose of this study was to investigate the reaction products formed by application of three tooth etchants to hydroxyapatite.

Methods: Tooth etchants with three different compositions, designed for application to teeth before dental adhesive - " K-etchant GEL" (containing phosphoric acid), "Enamel Conditioner" (containing organic acids), and "Multi Etchant" (containing acidic monomer) - were applied to hydroxyapatite plates.

Results: Atomic force microscopy measurements revealed that Multi Etchant formed nano-sized particles on the hydroxyapatite. X-ray diffraction and Fourier transform infrared spectrometer analyses of the powdered hydroxyapatite indicated that Enamel Conditioner produced calcium tartrate whereas K-etchant GEL generated monetite. These results indicated that each etchant reacted with hydroxyapatite in a different way.

Conclusion: Not only differences among the etching ability of etchants, but also differences in the reaction compounds they produce may influence bonding performance in clinical practice.

Purpose: The aim of this study was to determine the effect of polishing press-on force on surface roughness and gloss of computer-aided design-computer-aided manufacturing (CAD-CAM) composites.

Methods: The materials evaluated included a CAD-CAM ceramic, a polymer-infiltrated ceramic, and three filler-based CAD-CAM composites. The CAD-CAM blocks were sectioned, embedded in self-cured resin, finished with abrasive papers and ultrasonically cleaned. Specimens were subsequently polished using the Sof-Lex disk system with 0.5, 1.0, 1.5, and 2.0 N press-on force by means of a custom-made apparatus. Contour arithmetic mean deviation (Ra) and gloss value (GU) data were acquired with a profilometer and glossmeter, respectively, and analyzed using ANOVA/Bonferroni post hoc test and Pearson's correlation (α = 0.05). Representative samples of the various materials at baseline and after each polishing step were examined under scanning electron microscope.

Results: Mean Ra and GU values ranged from 0.096 ± 0.004 μm to 0.295 ± 0.045 μm and 13.4 ± 1.9 to 67.6 ± 11.3 correspondingly for the various material-force combinations. Surface roughness and gloss were found to be press-on force and material dependent. A moderately strong and negative correlation (r_s = -0.69) existed between Ra and GU values.

Conclusion: For optimal smoothness and gloss, ceramic and polymer-infiltrated ceramic CAD-CAM materials must be polished with a 2.0 N force, while filler-based CAD-CAM composites should, in general, be polished using a 1.0 to 1.5 N force.

Purpose: To investigate the effects of two ultrasonic vibration protocols for cast post removal (single or double ultrasound units) on the development of defects in root dentin.

Methods: Sixty bovine incisors were selected. Fifteen roots were left unprepared (control). Forty-five roots were instrumented and filled. A 10-mm post space was prepared using #1-4 Largo drills. Fifteen teeth were prepared for post space and received no further procedure. Thirty roots had cast posts cemented and were submitted to ultrasonic vibration protocols for removal. The time necessary to remove each post was recorded. Roots were sectioned 3, 6, 9, and 12 mm from the coronal portion and viewed through a 25× magnification in a stereomicroscope. The presence of root fractures, partial cracks, and craze lines was registered. Chi-square and Fisher's exact tests were performed to compare the incidence of dentin defects. The Kruskal-Wallis test was performed to explore the difference between the time needed for post removal. The significance level was set at P = 0.05.

Results: Root defects were observed in all experimental groups. There were no statistical differences comparing previous root canal treatment and post removal steps, either with 1 or 2 ultrasonic units, in the formation of defects (P = 0.544) or fractures (P = 0.679).

Conclusion: Ultrasonic vibration protocols for removing cast posts did not increase the number of dentin defects compared to root canal preparation and obturation and post space preparation steps.

Purpose: Methyl-CpG binding protein 2 (MeCP2)-deficient (Mecp2^-/y) mice exhibit apneas that resemble respiratory abnormalities observed in Rett syndrome (RTT) patients. The present study aimed to clarify whether Mecp2^-/y mice show diurnal variations in apnea as seen in RTT and how the MeCP2 deficiency affects monoaminergic systems that control breathing.

Methods: In 7-week-old Mecp2^-/y mice, 24 h variation of apnea and effects of milnacipran, a serotonin/noradrenaline reuptake inhibitor, on the apnea were evaluated. The number of vesicular monoamine transporter 2 (VMAT2)-immunoreactive puncta in the caudal medulla was counted. Further, the effects of valproate (VPA) on the expression of tyrosine hydroxylase (TH) mRNA in the ventrolateral medulla of mice were assessed by RT-qPCR.

Results: Apnea occurred more frequently during the light phase under a 12:12 h light/dark environment in Mecp2^-/y mice and milnacipran reduced apnea during the light phase but not during the dark phase. The number of VMAT2-immunoreactive puncta was reduced in Mecp2^-/y mice. VPA treatment significantly increased TH mRNA expression in Mecp2^-/y mice.

Conclusion: Alteration of monoaminergic systems in the caudal medulla of Mecp2^-/y mice is potentially relevant to the light-sensitive diurnal increase of apnea, and an improvement in monoaminergic neurotransmission can ameliorate the diurnal increase of apnea in Mecp2^-/y mice.

Purpose: The purpose of this study was to perform an in vitro evaluation of digital impressions using a mobile device and monoscopic photogrammetry in cases of orbital defects with undercuts.

Methods: Three 10-mm-square cubes were attached to a diagnostic cast of a patient with a right orbital defect. Still images acquired with a mobile device were used to generate facial three-dimensional (3D) data. Two types of still images were used: one was a whole face image, and the other was a defect site-focused image. For comparison, an extraoral scanner was used to obtain facial 3D data. Five dental technicians fabricated 3D printed models using additive manufacturing and measured the distances between the measurement points using a digital caliper. The discrepancy between the distances measured on the diagnostic cast of the patient and the 3D printed model was calculated. Friedman test was used to analyze the discrepancy, and the Bonferroni test was used to verify the differences between the pairs.

Results: Statistical significance was found with respect to the type of 3D model fabrication method.

Conclusion: Within the limitations of this in vitro study, the results suggested that the workflow can be applied to digital impressions of the maxillofacial region.

Purpose: To clarify the presence or absence of differences in path pattern and movement during mastication between the habitual and non-habitual chewing sides.

Methods: Participants were 225 healthy adults with natural dentition. Mandibular movement while chewing gummy jelly on each side was recorded, and masticatory path pattern was classified into five types (one normal and four abnormal). The frequency of each pattern was measured and compared between chewing sides. The amount, rhythm, velocity, and stability of movement and masticatory performance were measured and compared between chewing sides.

Results: A normal pattern was observed on the habitual chewing side in 84.4% of participants. There was a significant difference between chewing sides in masticatory path pattern (χ² = 35.971, P < 0.001). Values of parameters regarding the amount and velocity of movement and masticatory performance were significantly higher on the habitual chewing side. Values of parameters regarding rhythm and stability of movement were significantly lower on the habitual chewing side.

Conclusion: The present findings of functional differences between chewing sides in terms of path pattern and movement during mastication suggest that these factors should be analyzed on the habitual chewing side.

Purpose: To study the antimicrobial effects of a novel vinegar-based denture cleansing agent on oral Streptococci and Candida species and the inhibitory effects on pre-formed bacterial and Candida biofilms on denture base.

Methods: The microorganisms used in this study were Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Streptococcus sanguinis (S. sanguinis), Candida albicans (C. albicans), and Candida glabrata (C. glabrata). The antimicrobial activity of novel vinegar solution was evaluated by time kill assay and biofilm grown on denture base.

Results: Time kill assay showed that vinegar exhibited the highest antibacterial effect on S. sobrinus, S. sanguinis, and S. mutans after 15 min of treatment. A 99.9% reduction in C. glabrata and C. albicans required more than 4 and 6 h of treatment, respectively. Vinegar significantly inhibited streptococcal biofilm, with an approximately 6 log-reduction at 30 min of treatment. The results demonstrated that viable Candida cells in biofilm reduced in excess of 6-log CFU/mL after 3 h treatment with vinegar. Moreover, the vinegar-based denture cleanser inhibited bacterial and Candida biofilm formation compared to the control group without treatment with statistical significance.

Conclusion: A novel vinegar-based denture cleansing agent showed moderate antibacterial properties, but required a slightly longer immersion time to attain anticandidal effects compared to Polident and 0.2% CHX.