Effects of fixed orthodontic treatment on nickel and chromium levels in gingival crevicular fluid as a novel systemic biomarker of trace elements: A longitudinal study.

INTRODUCTION: Nickel and chromium might induce hypersensitivity. Therefore, they are of interest to orthodontists. Gingival crevicular fluid (GCF) is highly relevant to orthodontic treatments and might reflect systemic changes associated with the inflammatory response induced by orthodontic forces. Therefore, it might also be used to show metal ion changes. Nevertheless, baseline metal levels of GCF are unknown, and the effect of orthodontic treatment on GCF metal levels has not been investigated. The aim of this study was to assess the levels of nickel and chromium in GCF. METHODS: Based on a pilot study, the sample size was predetermined as 24 × 3 measurements to obtain test powers above 90%. Nickel and chromium concentrations were measured before treatment and 1 month and 6 months later in 12 female and 12 male patients who had fixed orthodontic appliances using atomic absorption spectrophotometry. The gingival index was also evaluated in each session. The effects of treatment on GCF ions were analyzed using repeated-measures analysis of variance and Friedman tests (α = 0.05, ß ≤0.01). RESULTS: The gingival index worsened over time (chi-square test, P <0.001). The mean nickel levels were 3.894 ± 1.442, 5.913 ± 2.735, and 19.810 ± 8.452 µg per gram, respectively, at baseline, month 1, and month 6. Chromium concentrations were 1.978 ± 0.721, 4.135 ± 1.591, and 13.760 ± 3.555 µg per gram, respectively. Compared with the baseline, nickel increased by 150% and 510%, respectively, in the first and sixth months (Friedman, P <0.0001), and chromium increased by 200% and 700%, respectively (analysis of variance, P <0.0001). CONCLUSIONS: Six months of fixed orthodontic treatment might intensify the levels of nickel and chromium in the GCF as well as gingival inflammation.

Shear bond strength of metal brackets to feldspathic porcelain treated by Nd:YAG laser and hydrofluoric acid.

Adult orthodontic treatment requires bonding orthodontic attachment to dental restorations. Ceramics are commonly used as esthetic restorative materials for the crowns and bridges. The present study evaluated the shear bond strength of metal orthodontic brackets to the feldspathic porcelain surfaces following conditioning by different powers of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and hydrofluoric acid as a conventional method. Seventy-two glazed porcelain samples were prepared and randomly attributed to six equal groups of 12. In the conventional hydrofluoric (HF) group, the specimens were etched by 9.6% hydrofluoric acid for 4 min. In laser groups, samples were conditioned by 0.75-, 1-, 1.25-, 1.5-, and 2-W Nd:YAG laser for 10 s. Metal brackets were bonded to porcelain samples and after being stored in distilled water for 24 h, they were subjected to thermocycling for 500 cycles. The debonding was carried out by a Zwick testing machine. The data were statistically analyzed by ANOVA and Tamhane multiple comparisons tests. The mean ± SD of the shear bond strength in the laser group 0.75, 1, 1.25, 1.5, and 2 W and HF group was 2.2 ± 0.9, 4.2 ± 1.1, 4.9 ± 2.4, 7 ± 1.7, 9.6 ± 2.7, and 9.4 ± 2.5, respectively. Together with the increased power of laser, the mean shear bond strength was increased continuously and no significant differences were found between the HF group and the laser groups with power of 1.5 or 2 W. Also, there was no significant difference between all test groups in ARI scores. There was no significant difference between bond strength of laser groups with power of 1.5 and 2 W and HF-etched group. So, Nd:YAG laser with appropriate parameters can be used as an alternative method for porcelain etching.

Detection of vertical root fractures using digitally enhanced images: reverse-contrast and colorization.

Root fracture diagnosis is a clinical difficulty that in most cases can only be detected through radiography. The objective of this study was to compare the diagnostic accuracy of two types of digitally enhanced images (reverse-contrast and colorization) with original digital radiographies in detecting experimental root fractures. Two hundred extracted single-rooted human teeth were endodontically instrumented and then divided in two groups, one control group and one test group, including fractured teeth. Vertical root fractures were experimentally made in the fractured group. The digital image of each tooth was taken, using the paralleling technique. There were three groups of images: (i) original, (ii) reverse contrast, and (iii) colorized. Three experienced dental specialists examined the images with no prior knowledge of the distribution of the root fractures. Two-way analysis of variance was used to assess the differences in accuracy, sensitivity, and specificity of each technique in detecting root fractures. Cohen's kappa coefficients were calculated to investigate the degree of interobserver agreement. The accuracy, sensitivity, and specificity of original images were 67.4%, 66.7%, and 68%, respectively; these amounts were 61.5%, 61%, and 65.5% in reverse contrast images and 66.4%, 70.7%, and 62% in colorized digital radiography. The original images had the best inter observer kappa coefficients (between 0.45 and 0.55). The results showed that the accuracy of original images is better than reverse contrast and colorized images. Use of reverse-contrast and colorization digital images in root fracture detection should be regarded as an adjunct to other diagnostic methods not as a highly critical diagnostic aid.

Effects of fixed orthodontic treatment and two new mouth rinses on gingival health: A prospective cohort followed by a single-blind placebo-controlled randomized clinical trial.

INTRODUCTION: Routine brushing protocols might not suffice to reduce the increased plaque accumulation in orthodontic patients. Antimicrobial mouth rinses are favorable in this regard. This two-phase study evaluated the effects of orthodontic treatment and the application of two mouthwashes not studied before on oral health indices. METHODS: In this two-phase study (a prospective cohort followed by a parallel randomized controlled trial), plaque index (PI), gingival index (GI), gingival bleeding index (GBI), and pocket probing depth (PPD) were measured in 54 orthodontic patients before orthodontic treatment and 4 months later. Then patients were randomized into three groups of mouthrinses: Persica (herbal), Ortho-Kin (containing diluted chlorhexidine), and Placebo (n=18×3). The effects of orthodontic treatment and mouthrinses were analyzed statistically (α=0.05). RESULTS: All the 4 indices increased between the baseline and 4th month of treatment (P values<0.01, paired t-test). They decreased back to baseline levels or below them, after one month of mouthwash application (P values<0.002). Both mouthwashes showed therapeutic effects compared to placebo in terms of PI and GBI. In the case of GI, only Persica showed significantly better results compared to placebo. Regarding PPD, only Ortho-Kin acted better than placebo (P values≤0.05, Tukey). LIMITATIONS OF THE RANDOMIZED CONTROL TRIAL (RCT) PHASE: Lack of positive control (regular chlorhexidine mouth rinse) and negative control (a group with no mouthwashes, even without the placebo). Lack of sample size predetermination based on a priori power calculations. The difference between the regime of Persica with that of Ortho-Kin and placebo (which had similar application protocols) disallowed perfectly effective blinding of the patients (hence, single-blind). CONCLUSION: Fixed orthodontic treatment might disrupt gingival health. Antimicrobial mouthwashes might reverse this. Both evaluated mouthwashes might have therapeutic effects.

Facial Anthropometric Norms of the Young Iranian Population.

INTRODUCTION: Facial anthropometric measurement is considered an essential concern of surgeons, orthodontists, artists and forensic scientists. The aim of this study is to investigate facial anthropometric norms of the young Iranian population. METHODS: The study participants consisted of 200 healthy Iranian students (100 males, 100 females) aged 18-25 years old. Twenty-three liner and four angular measurements were investigated twice by a dentist. Independent-samples t test was used to compare indices between males and females and also between countries. A p value less than 0.05 was considered statistically significant. RESULTS: It was found that the mean measurements of c'-sn' of both sides, nasolabial angle, trichion-gnathion, tragion-tragion and gnathion-gnathion were statistically greater in Iranian males than in females (p < 0.05). Comparing Iranian anthropometric norms with North American Whites, Malays, Turkish and African American women demonstrated that there were statistically significant differences in most anthropometric measurements between Iranians and other populations (p < 0.05). CONCLUSION: In Iranians, mean measurements of c'-sn' of the right and left sides, nasolabial angle, trichion-gnathion, tragion-tragion and gnathion-gnathion were greater in men than in women. Comparing Iranian males and females with different ethnicities indicated several interracial differences, which should be taken into consideration when dealing with patients or also practitioners originated in this region.

Cephalometric risk factors associated with myocardial infarction in patients suffering from obstructive sleep apnea: A pilot case-control study.

INTRODUCTION: Obstructive sleep apnea (OSA) and its craniofacial anatomic risk factors might play a role in several cardiovascular diseases, including myocardial infarction (MI). However, there are no data about cephalometric findings among OSA patients with MI. METHODS: In this pilot case-control study, about 2000 individuals referred to the sleep center were evaluated according to apnea - hypopnea index (AHI) and other inclusion criteria. Included were 62 OSA male patients (AHI > 10), of whom 6 had an MI history. In both control (n = 56) and MI groups (n = 6), 18 cephalometric parameters were traced. Data were analyzed using independent samples t-test. RESULTS: Compared with control OSA patients, OSA patients with MI showed a significantly larger tongue length (p = 0.015). The other cephalometric variables were not significantly different between the two groups. CONCLUSION: An elongated tongue might be considered a risk factor for MI in OSA patients. The role of other variables remains inconclusive and open to investigation with larger samples (determined based on pilot studies such as this report) collected in longitudinal fashion.

Prevalence and Length of the Anterior Loop of the Inferior Alveolar Nerve in Iranians.

The anterior loop of the inferior alveolar nerve is a sensitive anatomical feature that should be taken into account during installation of dental implants anterior to the mental foramen. This study was conducted to explore the controversy regarding prevalence and length. A total of 452 mandible quadrants of 234 patients (age: 50.1 ± 13.3 years, 113 males, 121 females) were studied using cone-beam computerized tomography. After reconstructing axial, frontal, and sagittal slices, the region between the most anterior point on the mental foramen and the most anterior part of the mandibular nerve was inspected for signs of anterior loop presence. If positive, the length of the anterior loop was measured in mm as the distance between the anterior border of mental foramen and the anterior border of the loop. Prevalence and length of the anterior loop were compared statistically between sexes and age groups. The anterior loop was observed in 106 quadrants (23.5% of 451 quadrants) of 95 patients (40.6% of 234 patients), of whom 11 had bilateral anterior loops. Prevalences were similar in males (41%) and females (39%, chi-square P =.791). The mean anterior loop length was 2.77 ± 1.56 mm (95% CI: 2.5-3.1 mm), without significant sex (regression beta = -0.159, P = .134) or age (beta = -0.059, P = .578) differences. The anterior loop might exist in about 40% of patients, regardless of their gender. The mean safe anterior distance from the anterior loop is about 3 mm + (2.5-3.1 mm) = 5.5-6.1 mm, regardless of age.

Cephalometric risk factors of obstructive sleep apnea.

INTRODUCTION: Previous studies on risk factors of obstructive sleep apnea (OSA) are highly controversial and mostly identifying a few cephalometric risk factors. METHODS: OSA diagnosis was made according to the patients' apnea-hypopnea index (AHI). Included were 74 OSA patients (AHI > 10) and 52 control subjects (AHI ≤ 10 + free of other OSA symptoms). In both groups, 18 cephalometric parameters were traced (SNA, SNB, ANB, the soft palate's length (PNS-P), inferior airway space, the distance from the mandibular plane to the hyoid (MP-H), lengths of mandible (Go-Gn) and maxilla (PNS-ANS), vertical height of airway (VAL), vertical height of the posterior maxilla (S-PNS), superior posterior airway space (SPAS), middle airway space, distances from hyoid to third cervical vertebra and retrognathion (HH1), C3 (C3H), and RGN (HRGN), the maximum thickness of soft palate (MPT), tongue length (TGL), and the maximum height of tongue). These parameters were compared using t-test. RESULTS: Significant variables were SPAS (p = 0.027), MPT, TGL, HH1, C3H, HRGN, PNS-P, S-PNS, MP-H, VAL, and Go-Gn (all p values ≤ 0.006). CONCLUSION: OSA patients exhibited thicker and longer soft palates, hyoid bones more distant from the vertebrae, retrognathion, and mandibular plane, higher posterior maxillae, longer mandibles, and smaller superior-posterior airways.

Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial.

OBJECTIVE: Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. METHODS: In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). RESULTS: In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). CONCLUSIONS: Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results.

Comparison of Carbon Dioxide Laser With Surgical Blade for Removal of Epulis Fissuratum. A Randomized Clinical Trial.

Introduction: Epulis fissuratum is often formed as a result of a poor fitting denture. The conventional treatment for this fibrous hyperplastic tissue is to excise it using a scalpel and to close the wound by a continuous or an interrupted suture. The increased utilization of lasers in dentistry also includes the utilization of carbon dioxide (CO2) lasers in place of surgical scalpels in soft tissue surgeries. The objective of this study is to assess the feasibility of utilizing CO2 laser in place of scalpel in surgical treatment of epulis fissuratum. Methods: In this clinical trial research (IRCT code: IRCT2016071124969N2), 19 patients were selected with nearly symmetrical epulis fissuratums in the anterior part of the jaws. The hyperplastic tissue was evenly divided into two sections in each patient. One section was randomly selected and cut by CO2 laser and the other section by a surgical scalpel. The wound created by the scalpel was closed by appropriate number of interrupted sutures. Surgery duration and bleeding as well as vestibular depth, re-epithelialization and edema in both sections were noted and recorded after 7 and 14 days postoperatively. Results: The time of surgery and the amount of bleeding during surgery in the laser section was less and the vestibular depth was more than surgical scalpel section (P < 0.05). Surgical scalpel wound at day seventh healed significantly better than the section treated by the CO2 laser (P < 0.05). Wound in both sections healed similarly on day 14 and no statistical difference was observed. Edema presence was also equal in both sides after 7th and 14th following the surgery. Conclusion: According to the results it could be concluded that the use of CO2 laser may result in less surgery time, less bleeding during surgery, more vestibular depth, better re-epithelialization of the wound and less need for suturing. CO2 laser may be a clinically preferred method for surgical treatment of epulis fissuratum.

Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

BACKGROUND: Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. METHODS: This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, ß > 0.99). This trial was not registered. It was self-funded by the authors. RESULTS: Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). CONCLUSIONS: Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study.

OBJECTIVE: The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. METHODS: This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (α < 0.05). RESULTS: The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 ± 915 A°, 1,378 ± 372 A°, 2,444 ± 369 A°, and 5,242 ± 2,832 A°, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 ± 210 A°, 1,831 ± 1,156 A°, and 4,018 ± 2,214 A°, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. CONCLUSIONS: The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires.