Dentistry Journal最新文献

The introduction of nickel-titanium rotary instruments revolutionized shaping procedures as they were able to produce a well-tapered preparation while reducing operator fatigue. The major drawback of rotary instruments was the high risk of fracture due to bending and torsional stress. Thus, the creation of a glide path has been advocated and recommended by most rotary instrument manufacturers. The aim of the present review is to summarize existing knowledge on glide path preparation and identify areas where further research is needed. The primary goal is to provide a comprehensive overview of the techniques and instruments used in glide path preparation, highlighting their advantages and limitations. The secondary goal is to explore the effect of glide path creation on the overall success of endodontic treatment, particularly in terms of reducing procedural errors and improving treatment outcomes. An online search on PubMed, ScienceDirect, UCLA, and Scopus databases was conducted, and 116 articles were identified. Eligible articles were divided into nine categories based on what they researched and compared. The categories included centering ability and/or root canal transportation, cyclic fatigue resistance, glide path and shaping time, tortional stress resistance, apical extrusion of debris and/or bacteria, defects in dentine walls, file separation, postoperative pain assessment, and scouting ability and performance. Establishing a glide path reduces root canal transportation, especially with rotary methods. Reciprocating and heat-treated files offer higher fatigue resistance and shorter preparation time. Instruments with shorter pitch lengths have greater torsional strength. Preparation and coronal preflaring reduce apical debris and bacteria. Glide paths do not affect dentine microcracks, file separation, or defects but reduce immediate postoperative pain and improve cutting ability. Randomized trials are needed to assess their impact on treatment outcomes.

Objective: This study examined the potential use of computed tomography panoramic mandibular indices on cone beam CT (CBCT) for assessing bone density in postmenopausal women with low bone mass.

Study design: The study enrolled 104 postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) using a DXA scanner and mental foramen region CBCT alongside the NewTom VGi EVO Cone Beam 3D system. We assessed the relationship between the following DXA parameters: lumbar, femoral neck, and total hip T score, bone mineral density (BMD), and lumbar trabecular bone score (TBS). The following panoramic mandibular indices were also considered: the computed tomography mandibular index superior (CTI(S)), computed tomography mandibular index inferior (CTI(I)), and computed tomography mental index (CTMI).

Results: The study revealed moderate correlations between CBCT indices and BMD/TBS scores: CTMI showed the highest correlation with the femoral neck T-score (r = 0.551, p < 0.0001). TBS scores were also moderately correlated with CBCT indices: CTMI showed a moderate positive correlation with TBS (r = 0.431, p < 0.0001); CTI(S) had a similar moderate positive correlation with TBS (r = 0.421, p < 0.0001). AUC values ranged from 0.697 to 0.733 for osteoporosis versus the osteopenia/normal group and from 0.734 to 0.744 for low versus normal bone quality groups, p < 0.0001. The comparison of the values of the studied indices between low versus normal bone quality (quantified with TBS) groups showed high sensitivity but low specificity.

Conclusions: CBCT-measured indices CTI(S), CTI(I), and CTMI are useful in assessing patients with low bone mass to improve, by specific treatment, the prognosis of dental implants.

Objectives: Orthodontists are often asked to remove fixed retainers before patients undergo magnetic resonance imaging (MRI). The present in vitro study was designed to analyze the heating and bonding efficacy of stainless steel multibraided fixed retainers after 1.5- and 3-tesla (T) MRI.

Materials and methods: A total of 180 human mandibular incisors were used to create 45 specimens of four teeth each, divided into nine groups. Handmade multibraided fixed retainers of three different sizes, defined by the diameter of the initial wire used (0.008″, 0.010″ and 0.012″), were tested. Three groups underwent MRI at 1.5 T, another three groups underwent MRI at 3 T and the last three groups did not undergo MRI. Temperature was assessed before and after MRI. Shear bond strength (SBS) and adhesive remnant index (ARI) were assessed after MRI for all groups. Data were statistically analyzed (p < 0.05).

Results: After 1.5 T exposure, no significant temperature increase from T0 to T1 was observed in any of the groups (p > 0.05). Regarding the 3 T groups, a significant difference from T0 to T1 was found for all the groups (p < 0.05). Temperature changes were not clinically relevant, as they were less than 1 °C for all groups except for group 3 (ΔT0-T1: 1.18 ± 0.3 °C) and group 6 (ΔT0-T1: 1.12 ± 0.37 °C). Furthermore, there were no significant differences between the temperature variations associated with different wire diameters (p > 0.05).

Conclusions: No significant changes in SBS or ARI were found (p > 0.05).

Clinical significance: Since overheating was irrelevant and adhesion values did not change, the tested devices were concluded to be safe for MRI examinations at 1.5 T and 3 T.

(1) Background: The objective of this study was to evaluate the efficacy of the Rapid Maxillary Expander (RME) II System compared to a Herbst appliance and a control group in the treatment of class II skeletal malocclusions in growing patients. (2) Methods: A total of 30 class II patients treated using the RME II System (group R) were compared with 30 patients treated with a Herbst appliance (group H) and 30 untreated class II children (group C). Cephalograms were compared at the start (T0) and after 24 months (T1). Nine cephalometric parameters were analyzed: SN-MP, SN-PO, ANB, AR-GO-ME, AR-GO-N, N-GO-ME, SN-PP, LFH, CO-GN, 1+SN, IMPA, OVERJET, and OVERBITE. Since the variables failed the normality test, a Wilcoxon test was performed for a pairwise comparison of the cephalometric measurements taken at T0 (pre-treatment) and at T1 (post-treatment). ANOVA with Tukey post hoc correction was used to evaluate the differences among the groups. (3) Results: ANOVA showed a statistically significant difference for all analyzed variables except for AR-GO-ME, AR-GO-N, and N-GO-ME. Post hoc Tukey's HSD test showed the following difference: the SN-PO angle in group H was 3.59° greater than in group R; the LFH in group H was 4.13 mm greater than in group R. The mandibular length (CO-GN) in group H was 3.94 mm greater than in group R; IMPA in group H was 6.4° greater than in group R; and the ANB angle in group H was 1.47° greater than in group R. (4) Conclusions: The RME II System is an effective therapeutic device for class II skeletal malocclusion treatment in growing patients.

(1) Background: Musculoskeletal disorders (MSDs), discomfort, fatigue, pain, and other acute and chronic work-related injuries are common among dental clinicians. Hand instruments constitute a primary risk factor for these conditions. The overall goal of this study was to compare in dental hygienists with healthy hands, and in those with MSDs, the effect of three different handle designs on instrumentation-related muscle work, comfort, fatigue, and quality of tactile feedback. (2) Methods: Clinicians tested three periodontal curettes: one with a novel adaptive silicone handle, another with a rigid resin handle, and the third with a rigid silicone handle. Ten hygienists-five with MSDs and five without-each scaled three typodonts using the three different curettes. Statistical analysis was performed using a General Linear Model (GLIM) and Tukey's post hoc test, and a significance level of p < 0.05 was implemented. (3) Results: On average, mean comfort and fatigue across all instruments were significantly worse in testers with MSDs, who also expended significantly more work to complete the same task. In all testers, a novel adaptive handle design was associated with significantly reduced total muscle work and post-instrumentation fatigue, as well as better comfort than conventional rigid handle designs. (4) Conclusions: An adaptive curette handle design demonstrated significantly better ergonomic outcomes than conventional rigid curette handle designs. Hygienists with MSDs expend significantly more muscle work during dental instrumentation.

Background: Postoperative resorption of hard and soft tissues occurs as a consequence of tooth extraction. The Benex^®-Control extractor allows minimally invasive extraction of the tooth without causing pronounced iatrogenic trauma. The aim of this study was to verify whether the resorption of the tissues after extraction can be reduced by using the Benex^® system compared to the conventional extraction method.

Methods: Postoperative intraoral scans were superimposed after surgery (t0), after 7 days (t1), after 14 days (t2), after 30 days (t3), after 60 days (t4), and after 90 days (t5) within the two groups (study n = 14, control n = 16), and defined regions of interest (ROIs) (1-8) and volume changes were analyzed. In addition, the influence of gingival thickness and the thickness of the labial cortical plate was investigated.

Results: The greatest decrease in volume was observed in both groups in ROI3, although there was no significant difference observed between the groups. In the presence of an adjacent tooth, there was less volume loss in the affected ROIs (1, 2 and 7, 8). The thickness of the gingiva and the bony lamella did not significantly influence the change in volume.

Conclusions: Due to the small cohort, the results are limited, and the hypothesis is rejected.

(1) Background: The aim of this study was to compare the cytotoxicity of selected resin-modified materials used in direct contact with the dental pulp (TheraCal LC, TheraCal PT, and ApaCal ART) with calcium silicate cement (Biodentine). (2) Methods: The mouse fibroblast Balb/3T3 cell line and the extracts of tested materials in four concentrations were used for the testing. An MTT assay was performed in three independent experiments with six replicates for each concentration of tested material. The cell viability (%) and cytotoxicity were expressed (cytotoxic effect is considered in cases where the cell viability is lower than 70%). The mean of the cell viability and the standard deviation were expressed for each material at all concentrations. ANOVA and Dunnet's post hoc tests were used for the statistical analysis. All of these tests were performed at the 0.05 significance level. (3) Results: At all concentrations, the cell viability was statistically significantly lower (p ≤ 0.002) for all tested materials compared to Biodentine. ApaCal ART showed a high level of cytotoxicity at all concentrations (cell viability lower than 47.71%, p < 0.0001). The same result was found for TheraCal LC at concentrations of 100%, 50% and 25% and TheraCal PT at concentrations of 100% and 50%. TheraCal LC at a 10% concentration (cell viability 68.18%) and TheraCal PT at a 25% concentration (cell viability 60.63%) indicated potential cytotoxicity. TheraCal PT at a 10% concentration was not found to be cytotoxic (cell viability 79.18%, p = 0.095). (4) Conclusion: The resin-modified calcium silicate and calcium phosphate materials showed higher cytotoxic potential, so they should be used with caution when in direct contact with the dental pulp.

The objective of this prospective 12-month observational study is to examine the oral health-related quality of life (OHRQoL) among Hong Kong young children aged 3-4 years old receiving silver diamine fluoride (SDF) therapy for carious upper anterior primary teeth. A parental questionnaire was used to collect each child's sociodemographic background and oral health habits at baseline. Data on parents' satisfaction with their child's dental aesthetics were collected at baseline and during a 12-month visit. The Chinese Early Childhood Oral Health Impact Scale (C-ECOHIS) was used to measure OHRQoL. A trained dentist performed examinations and recorded caries experience (dmft) and oral hygiene (visible plaque index) at baseline and 12 months. SDF was applied to the carious lesions. Out of 286 invited children, 248 (87%, 248/286) participated, and 211 (85%, 211/248) attended the 12-month examination. All SDF-treated carious lesions were discoloured at the 12-month examination. Regression analysis showed that the baseline C-ECOHIS score was associated with dmft (p < 0.001). The baseline and 12-month C-ECOHIS scores were 4.6 ± 5.5 and 5.0 ± 5.6, respectively (p = 0.42). The scores for parental satisfaction with dental aesthetics at baseline and 12 months were 59% to 46% (p < 0.001). Satisfaction was negatively associated with the number of discoloured upper anterior teeth (p < 0.001). In conclusion, SDF discoloured the carious upper anterior teeth of the Hong Kong kindergarten children. However, the discoloured lesions had no significant effects on the OHRQoL of these children. However, more parents became dissatisfied with their child's dental aesthetics after SDF therapy. Hence, clinicians should inform parents well before they perform SDF therapy on children.