A Quantitative Evaluation of the Effectiveness of the Metal Artifact Reduction Algorithm in Cone Beam Computed Tomographic Images with Stainless Steel Orthodontic Brackets and Arch Wires: An Ex Vivo Study

The presence of high-density and high-atomic number materials results in the generation of artifacts in cone beam computed tomographic (CBCT) images. To minimize artifacts in CBCT images, the metal artifact reduction (MAR) tool was developed. This study aims to quantitatively evaluate the effectiveness of the MAR algorithm in CBCT images of teeth with stainless steel orthodontic brackets with or without arch wires in buccal and lingual positions obtained using the Galileos Sirona CBCT scanner. In this in vitro study, 20 stainless steel brackets were attached to the maxillary dentition from the right second premolar to the left second premolar teeth of a human skull. In the first group, 10 brackets were bonded to the buccal surface, and in the second group, 10 brackets were bonded to the palatal surface of these teeth. CBCT scans were obtained for each group with or without orthodontic stainless steel wires using a Galileos Sirona CBCT scanner with exposure parameters of 85 kVp and 21 mAs. CBCT images were obtained two times with and two times without MAR activation. The DICOM format of the CBCT images was imported to ImageJ software (version 1.54), and the contrast-to-noise ratio (CNR) was calculated and compared for each bracket in 15 and 20 mm distances and 20, 40, and 90 degrees on each side. Statistical analysis was performed using the t test (α = 0.05). CNR values of different distances and different teeth were not significantly different between the two MAR modes (p > 0.05). MAR activation had a significant impact in increasing CNR and reducing artifacts only when brackets were in palatal (p = 0.03). In the other bracket and wire positions, the effect of the MAR algorithm on CNR was not significant (p > 0.05). In conclusion, MAR activation significantly increased CNR, but only when the brackets were in a palatal position. In the other bracket and wire positions, the effect of the MAR algorithm is not significant.

The effect of multiple enamel conditioning on enamel micro-hardness

BACKGROUND

White spot formation is one of the common side effects in orthodontic treatments and multiple enamel conditioning might happen even during on session of fixed orthodontic treatments. The aim of the present study was to evaluate the impact of multiple enamel conditioning with different methods on enamel micro-hardness (MH).

MATERIALS AND METHODS

In this In vitro experimental study, the buccal surfaces of 105 extracted premolars were evaluated in seven groups: One control and six experimental groups. The enamel conditioning was performed in three ways: Etching with phosphoric acid 37%, etching with phosphoric acid 37% followed by primer application and conditioning with self-etch primer. The conditioning process in each way was also performed twice consecutively. The specimens were submitted in pH cycling model with demineralization and re-mineralization solutions for 14 days. Afterward Vickers MH test was applied with 0.981N force on the teeth for 10 s indentation time. Data were analyzed using One-Way ANOVA and Tukey HSD (honestly significant difference) test for multiple comparisons. A value of P < 0.05 was considered statistically significant.

RESULTS

MH analysis showed statistically significant differences between the control group and the other conditioned groups (P < 0.05). The groups conditioned with acid-etch and primer, particularly twice, showed the lowest amount of MH in comparison to other groups. Self-etch primer had the least effect on MH of the enamel. Single time etching without using primer, made no considerable difference when compared to multiple etching.

CONCLUSION

Etching process and covering the enamel with primer decrease enamel MH. Using self-etch primer is a more conservative method of enamel conditioning.

Oral health-related quality of life and orthodontic treatment need in thalassemia major patients

Background

Thalassemia major (TM) is a severe life-threatening hemoglobinopathy. It causes a typical chipmunk face due to increased hematopoiesis. Severe malocclusion often accompanies facial deformity, which may affect Oral Health-related Quality of Life (OHRQoL). The aim of this study was to assess the relationship between orthodontic treatment needs and OHRQoL in TM patients.

Materials and Methods

One hundred and five adult patients with TM participated in this cross-sectional study. Oral Health Impact Profile-14 (OHIP-14) questionnaire was used to measure OHRQoL and the patient's need for orthodontic treatment was evaluated using the Index of Orthodontic Treatment Need (IOTN). The comparison of OHIP-14 scores between groups regarding orthodontic treatment need was carried out using t-test (SPSS software); P < 0.05 was considered statistically significant.

Results

The mean age of participants was 24.92 (±9.33) years, with 52% female versus 48% male. Orthodontic treatment need was 27.6%. The mean score of OHIP-14 was 12.95 (±7.02). A statistically significant relationship was found between OHIP-14 score and age, gender, and orthodontic treatment need (P < 0.05). All domains of OHIP-14 were significantly related to orthodontic treatment need (P < 0.05), except for "physical disability" (P = 0.282).

Conclusion

OHRQoL was lower in TM patients with orthodontic treatment needs. Planning to treat malocclusion seems necessary to improve the quality of life in these patients.

The efficacy of herbal medicine in the treatment of recurrent aphthous stomatitis: A systematic review of randomized clinical trials

This systematic review was undertaken with the main aim of assessing the therapeutic effects of herbal medicines in recurrent aphthous stomatitis (RAS). A comprehensive search was performed in PubMed, Scopus, ISI Web of Science, and Google Scholar up to July 2021 to identify randomized clinical trials investigated the effects of herbal medicines on RAS. Thirty-three papers comprising 2,113 patients met the eligibility criteria, of which 30 studies had a high quality based on the Jadad scale. Totally, 22 out of 30 studies which assessed the pain showed that herbal agents significantly decreased the pain compared with the control group or placebo. In 17 out of 25 studies that evaluated ulcer size, herbal agents significantly reduced the size of ulcers compared with the control or placebo groups. In 15 out of 18 studies that assessed the healing time, herbal agents significantly reduced healing time in the intervention groups compared with the placebo or control groups. Few adverse events were reported only in four studies. Findings of the current review indicated medicinal plants and phytochemicals as effective and safe agents that for the treatment of RAS.

Evaluation of the preventive effect of two concentrations of xylitol varnish versus fluoride varnish on enamel demineralization around orthodontic brackets: a randomized controlled trial

BACKGROUND

The highly prevalent white spot lesions around orthodontic brackets necessitate introducing preventive materials without relying on patient compliance.

OBJECTIVE

To evaluate the antidemineralizing effect of two concentrations of xylitol varnish.

TRIAL DESIGN

Triple-blind, four-arm, parallel-group, single-center, randomized controlled clinical trial.

METHODS

A total of 120 orthodontic patients were randomly assigned to four groups (n = 30), using a computer-generated randomized block list. The treatment groups were: 10% xylitol, 20% xylitol, 5% fluoride, and placebo. Tooth demineralization was measured with DIAGNOdent at T1 (before treatment), followed by varnish application. At T2 (third month), the varnish was re-applied, and at the third (T2) and sixth (T3) months, and after treatment (T4), the demineralization was measured. The white spot lesion frequency was assessed visually after treatment. The participants, the clinician, and data assessors were all blinded to group assignments.

RESULTS

A total of 115 patients underwent per-protocol analyses. At T2, the mean DIAGNOdent numbers in the fluoride and 10% xylitol groups were significantly lower than the placebo group (P = 0.00), with a mean difference of 0.63 (95% CI, 0.15-1.10) and 0.5 (95% CI, 0.04-0.95), respectively. At T3, the fluoride and 10% xylitol groups had significantly lower mineral loss than the placebo group (P=0.046) with a mean difference of 0.52 (95% CI, 0.14-0.89) in the fluoride and 0.45 (95% CI, 0.03-0.86) in the 10% xylitol groups, respectively. However, at T4, only the mean for the 10% xylitol group was significantly different (P=0.049) from the placebo group, with a mean difference of 1.18 (95% CI, 0.42-1.93). Visual assessment showed that after treatment, the prevalence of white spot lesions in the fluoride (P=0.03) and 10% xylitol (P=0.00) groups was less than the placebo group with the odds ratio of 0.67 (95% CI, 0.46-0.96) and 0.43 (95% CI, 0.28-0.64), respectively.

CONCLUSION

The 10% xylitol varnish short-term effects on caries control were significantly greater than 20% xylitol varnish and placebo but similar to fluoride varnish. However, the 10% xylitol long-term effect was almost better than fluoride varnish.

TRIAL REGISTRATION

The protocol was registered at IRCT.ir under the code IRCT20180913041032N1.

The effects of the headgear therapy on the airway dimensions in patients with class II malocclusion: A systematic review

Class II malocclusion may be caused by the maxillary protrusion or the mandibular retrusion. One treatment method is to use a headgear, which might affect the dimensions of the patient's airway. The aim of this study was to assess the effect of a headgear on the airway dimensions in class II malocclusion patients. A digital search and a manual search were conducted for English-language articles published from January 2000 to December 2018 about human clinical trials, including the usage of a cervical headgear in class II malocclusion patients who had measurable changes in the airway and/or jaw size. The synthesis methods of the study consisted of data concerning the study design, the type of treatment device, the patient's age at the start, the sample size, the treatment duration, the type of radiography, and the results of treatment; this data was extracted and compared. The quality of the selected articles was assessed. All of the studies had a high risk of bias, providing low-quality evidence of the effectiveness of the headgear therapy on the airway dimensions. The conclusions of the articles differed from each other and there were different mechanisms of changes in the jaw or airway dimensions. Therefore, further studies are required to find the clearest results showing the effect of a cervical headgear in class II malocclusion.

Changes of nasolabial angle from rest to smile in relation to cephalometric parameters

INTRODUCTION

The nasolabial angle (NLA) plays an important role in evaluating a patient's profile and smile appearance. The purpose of this study was to evaluate the changes of the NLA during smile and to correlate those changes with other photographic and cephalometric parameters.

METHODS

Fifty young adults ranging from 20 to 30 years of age who had been referred to a private dental clinic for orthodontic treatment for normal maxillary position were enrolled. For the purpose of this study, the angular measurements of the NLA and its compartments as well as changes in the vertical position of the nasal tip were collected from photographs taken at rest and during smile, while other parameters were measured from the lateral cephalograms taken with the head in a natural position. Changes in the NLA were then correlated with the cephalometric parameters in order to observe any potential relationships.

RESULTS

The NLA and its upper compartment decreased during smile (with a mean of 5.42 and 0.77 degrees, respectively). The NLA and its lower compartment increased, with a mean of 3.97 degrees. The nasal tip significantly dropped down from rest to smile (mean = 1.6 mm, P = 0.002). Significant correlations were found between changes of the NLA and the maxilla projection as well as between changes of the lower part of the NLA and the upper lip curvature.

CONCLUSIONS

Decreasing the NLA during smile is mainly related to the inherent properties of the soft tissues of the nasolabial area and not to the dental parameters under the control of the orthodontist. Patients should therefore be made aware of this from the beginning of the treatment.