Purpose: The aim of this investigation was to determine whether the facial esthetics of subjects rated as “attractive” can be related to specific cephalometric soft tissue parameters.

Methods: The profile silhouettes of 100 subjects (45 males and 55 females) were rated by 60 esthetics specialists (20 orthodontists, 20 dentists, and 20 plastic surgeons) using a Likert scale, and 30 of the subjects were selected as being “attractive”. The cephalometric measurements of the attractive group were then compared with norms for the general Caucasian population.

Results: The effects of specific measured parameters on profile beauty grades were assessed using the median test, and the following variables were found to show significant correlations between the Caucasian norms and the attractive profile group: the ratio of the upper to lower face height (P = 0.011), the ratio of the subnasale – labrale inferius (Sn-Li) and labrale inferius – menton (Li-Me`) lines (P = 0.011), the distance between the chin and the subnasale perpendicular (P = 0.002), upper lip thickness (P = 0.021), soft tissue chin thickness (P = 0.021), vertical height ratio (P = 0.021), and nasolabial angle (P = 0.021).

Conclusion: A straight profile with a fuller and more protruded upper lip, a higher nasal tip, and a smaller lower facial third are considered to be the most attractive facial features, and may be useful for improvement of facial esthetics.

Purpose: Inhibitory synaptic currents from fast-spiking neurons (FSNs), a typical gamma-aminobutyric acid (GABA)ergic interneuron in the cerebral cortex, to pyramidal neurons are facilitated by insulin. FSNs frequently show electrical synapses to FSNs, however, the effect of insulin on these electrical synapses is unknown. The aim of this study was to evaluate effects of insulin on electrical synaptic potentials between FSNs.

Methods: Electrical synaptic potentials via gap junctions between FSNs were recorded to examine how insulin modulates these potentials in the rat insular cortex (IC).

Results: Bath application of insulin (10 nM), which increases the spike firing rate of pyramidal neurons and unitary inhibitory postsynaptic currents recorded from FSN to pyramidal neuron connections, slightly but significantly increased electrical synaptic currents. The mean ratio of electrical synapses, the coupling coefficient that is obtained by postsynaptic voltage responses divided by presynaptic voltage amplitude, was 8.3 ± 1.1% in control and 9.2 ± 1.1% (n = 14) during 10 nM insulin application. Input resistance and voltage responses to large hyperpolarizing currents (−140 pA) were not changed by insulin.

Conclusion: These results suggest that insulin facilitates spike synchronization by increasing electrical synaptic currents via gap junctions of GABAergic FSNs in the IC.

Purpose: To evaluate the effect of intra-radicular cleaning protocols after post-space preparation (PSP) on marginal adaptation of a luting agent to root dentin.

Methods: Eighty bovine incisors were sectioned transversely to obtain 18-mm-long root sections. The roots were prepared with ProTaper instruments and filled using Tagger’s hybrid technique. PSP was performed at a length of 14 mm using #3-5 Largo drills. The roots were distributed into eight groups according to the chelating solution used (17% EDTA or 0.2% Chitosan) and the chelating activation/delivery method employed (conventional needle irrigation [CNI], EndoActivator [EA], XP-Endo Finisher [XPF] or passive ultrasonic irrigation [PUI]). The fiber posts were cemented using self-adhesive resin cement, and the roots were sectioned to obtain three discs from each root third. The dentin discs were observed under an optical microscope at ×40 magnification to assess marginal adaptation. The different protocols were compared considering the frequency of the marginal adaptation scores using the Kruskal-Wallis test, followed by the Dwass-Steel-Critchlow-Fligner test (α = 5%).

Results: The use of 17% EDTA resulted in better marginal adaptation (P < 0.001). PUI yielded results that were similar to those for EA (P = 0.949) and superior to those for XPF (P = 0.020). The combination of 17% EDTA + PUI provided a greater number of interfaces without marginal gaps (P < 0.001).

Conclusion: The cleaning protocol influenced the marginal adaptation of resin cement to root dentin.

Purpose: Osteoradionecrosis of the jaw is a therapy-resistant condition that may occur after treatment for head and neck cancer. The aim of this study was to investigate the incidence of osteoradionecrosis in patients with oropharyngeal cancer in relation to tooth extraction prior to radiation therapy.

Methods: Patients who had undergone radiation therapy for oropharyngeal cancer 5-10 years earlier were included and evaluated for the development of osteoradionecrosis (n = 75).

Results: Among the 75 patients, 62 had molar teeth present in the >50 Gy radiation field and 36 of those patients had teeth extracted prior to radiation therapy. Extraction of molars before radiotherapy significantly increased the risk of developing osteoradionecrosis (P < 0.05). There were no identifiable statistically significant correlations between the time from tooth extraction and the start of radiation therapy, the number of teeth in the radiation field, smoking habits, human papillomavirus-status, gender, age or tumor location and the development of osteoradionecrosis.

Conclusion: Tooth extraction prior to radiation therapy increases the risk of developing osteoradionecrosis. For patients with good oral hygiene and absence of dental disease, avoidance of tooth extraction in the radiation field could therefore reduce the risk of complications.

Purpose: The purpose of this study was to conduct basic research on the possibility of using cartilage tissue for hard-tissue reconstruction and to observe morphological changes in the transition of the cartilage to bone.

Methods: A 4-mm diameter bone defect was created in the right mandibular angle of rats. Cartilage, autologous bone, and artificial bone were grafted into the defect. Computed tomography (CT) was performed to measure the increase in bone volume. Further histological evaluation of the grafted site was performed.

Results: At 12 weeks, CT show that bone formation in the costal cartilage group was comparable to that in the autogenous bone group. Histologically, in the artificial bone group, a clear boundary was observed between the existing bone and defect, whereas in the costal cartilage and autologous bone groups, laminar plate bone repair of the defect was observed.

Conclusion: The findings in this study suggest that bone reconstruction achieved with cartilage grafting is almost equivalent to that with autogenous bone grafting and that bone reconstruction using cartilage is clinically feasible. In future, if regenerated cartilage is successfully applied clinically, bone reconstruction using regenerated cartilage may be feasible.

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: To compare the plaque-removal efficacy of ultra-soft single-headed, triple-headed, and T-shaped toothbrushes and the subjective perceptions of users.

Methods: In this randomized, single-blind, crossover study, 30 healthy adult participants were randomly divided into three groups of 10, who tested the three types of toothbrushes in differing order, with a 1-week washout period between the tests. Dental plaque scores were recorded before and after toothbrushing, and questionnaires on subjective perceptions after toothbrushing were collected.

Results: The participants included 16 female participants and 14 male participants (average age: 29.4 ± 6.7 years). All three toothbrush types were effective in reducing dental plaque by 36-46%; however, the cleaning effect of the ultra-soft single-headed toothbrush was inferior to that of the triple-headed and T-shaped toothbrushes, the difference being statistically significant. The users’ subjective perceptions suggested that the ultra-soft single-headed toothbrush was significantly superior to the other two toothbrush types. Plaque scores for the lower posterior tooth surfaces were higher than those for the upper posterior tooth surfaces, particularly on the left side, for both the ultra-soft single-headed and T-shaped toothbrushes.

Conclusion: Healthcare practitioners should identify the type of toothbrush bristles used by individuals and provide appropriate oral health information.

Purpose: Second-hand smoke has adverse effects on oral health. This cohort study used a multilevel approach to investigate the association of second-hand smoke exposure, as determined by salivary cotinine level, with dental caries in adolescents.

Methods: Data from 75 adolescents aged 11 or 12 years and 2,061 teeth without dental caries were analyzed in this study. Annual dental examinations to assess dental caries were conducted between 2018 and 2021. Salivary cotinine and Dentocult SM-Strip level were measured at baseline. Information on the smoking habits of parents, snack frequency, regular dental visits, and use of fluoride toothpaste was collected at baseline from parent-reported questionnaires.

Results: During the 3-year follow-up, dental caries was noted in 21 adolescents and 43 teeth. Participants exposed to parental smoking had higher salivary cotinine levels than those whose parents did not smoke. The multilevel Cox regression model showed that a high salivary cotinine level was associated with the incidence of dental caries, after adjusting for potential confounding factors (hazard ratio, 3.39; 95% confidence interval 1.08-10.69).

Conclusion: This study suggests that the risk of dental caries is higher for adolescents who have high salivary cotinine levels attributable to second-hand smoke exposure.

Purpose: Transient receptor potential canonical 1 (TRPC1) modulates tumor growth and invasion, however, its role in tongue squamous cell carcinoma (TSCC) is unclear. The aim of this study was to explore the effect of TRPC1 knockdown on cellular function and its underlying molecular mechanism in TSCC.

Methods: TSCC cell lines were transfected with TRPC1 or negative control small interfering ribonucleic acids, and then PI3K activator was incubated after transfection.

Results: TRPC1 was elevated in TSCC cell lines (including SCC-15, CAL-33, HSC-3, and YD-15) compared to control cells (all P < 0.05). Since TRPC1 was clearly increased in SCC-15 and YD-15 cells, they were selected for further study. In both YD-15 and SCC-15 cells, TRPC1 knockdown decreased cell proliferation at 48 h and 72 h (all P < 0.05), increased apoptosis (both P < 0.05), and declined invasion (both P < 0.05). Meanwhile, TRPC1 knockdown decreased phosphatidylinositol 3-kinase and protein kinase B phosphorylation (all P < 0.05). Additionally, the effect of TRPC1 knockdown on cell proliferation at 48 h and 72 h, apoptosis, and invasion was attenuated by PI3K activator (all P < 0.05).

Conclusion: TRPC1 shows potential as a candidate treatment target, whose knockdown inhibits growth and invasion through inactivating PI3K/AKT pathway in TSCC.

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.

Purpose: Today, bulk-fill composites are used as a single layer with a thickness of up to 4-5 mm. However, is proper polymerization achieved with this increased thickness?

Methods: This study was designed to investigate the effect of thickness on the degree of conversion (DC) (n = 6), the elution of monomers (n = 6), depth of cure (DoC) (n = 10) and cytotoxicity (n = 6) of the bulk-fill composites SDR Flow Plus (SDR), SonicFill2 SingleFill (SF) and ACTIVA Bioactive Restorative (ACT) in comparison to the conventional G-aenial Posterior (GC). Two‐way analysis of variance (ANOVA) was used to assess the interaction between materials and surfaces, and one‐way ANOVA and Tukey tests were used to compare the degree of conversion, monomer elution and cytotoxicity values (P < 0.05).

Results: The highest DC was found at the top surface of SDR, while the lowest DC was found at SF. The V2 mm/V0 mm DoC ratios of the composites except ACTs were appropriate according to the threshold. None of the composites were cytotoxic on day 1.

Conclusion: In bulk-fill composites, DC decreased and monomer elution increased with increasing depth. The V4 mm/V0 mm ratios of all bulk-fill groups were not appropriate. Additionally, only ACTs had a cell viability of <70% on day 7.

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: 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: This study aims to evaluate the effect of applying different parameters of nonthermal argon plasma (NTAP) on the surface roughness and phase transformation of yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics.

Methods: A total of 60 zirconia samples were prepared and randomly divided into six groups according to their surface treatments (n = 10). Group 1: control group; Group 2: argon plasma with a flow rate of 5 lt/min for 4 min; Group 3: 8 lt/min for 4 min; Group 4: 8 lt/min for 2 min; Group 5: 5 l/min for 2 min; Group 6: air abrasion with Al₂O₃ particle. The surface roughness was measured with a profilometer, and surface topography was observed using scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis was performed to investigate the phase transformation.

Results: The air abrasion group showed the highest surface roughness. The lowest relative monoclinic phase amount (Xm) was observed in the control group (0.4%), and the highest Xm value was observed in group 6 (7.8%).

Conclusion: While the air abrasion group showed the highest average surface roughness, it also caused the highest phase transformation. With a flow rate of 8 lt/min for 2 min NTAP treatment increased the surface roughness without causing significant phase transformation.

Purpose: To evaluate the effect of adding wollastonite and bioactive glass to an experimental mineral trioxide aggregate-like cement (MTA) on the dimensional stability, compressive strength, solubility, bioactivity, and marginal adaptation by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Methods: Four groups were evaluated at 7, 14, and 21 days: MTA Angelus, experimental MTA-like cement (MTA Exp), BG10 (MTA Exp+10 wt% bioactive glass), and WO20 (MTA Exp+20 wt% wollastonite). To evaluate marginal adaptation, extracted teeth were endodontically obturated and root-end cavities were prepared and filled with the tested materials.

Results: Cements with bioactive materials showed minimal dimensional changes. Adding wollastonite or bioactive glass to MTA Exp reduces the compressive strength but does not affect solubility. Bismite (Bi₂O₃), larnite (Ca₂SiO₄), calcite (CaCO₃) and carbonated hydroxyapatite (Ca₅[PO₄,CO₃]₃[OH]) were identified in the four cements; ettringite (Ca₆Al₂[SO₄]₃[OH]₁₂·26H₂O) and bismutite ([BiO]₂CO₃) were only observed in MTA Exp, BG10, and WO20. Cement-dentin interfaces were not observed after 14 days on the BG10 and WO20 cement composites due to the ettringite formation.

Conclusion: Acicular growing crystals typical of hydroxyapatite were found on the surfaces of all cements. An improved marginal adaptation was observed with the addition of wollastonite or bioactive glass.