Effect of mesenchymal stem cells with platelet-rich plasma carriers on bone formation after rapid maxillary expansion: An Animal Study.

OBJECTIVE: To evaluate the effect of bone mesenchymal stem cells (BMSCs) with or without platelet-rich plasma (PRP) carriers on sutural new bone formation after rapid palatal expansion (RPE). SETTINGS AND SAMPLE POPULATION: Sixty male Wistar rats were used in this study. MATERIAL AND METHODS: All samples were subjected to 50cN of palatal expansion force for 7 days followed by 3 weeks of the retention period. The experimental groups received a single-dose injection of the specified solution at the time of retainer placement (BMSCs, PRP, BMSCs+PRP, normal saline). BMSCs used in this study were marked with the green fluorescent protein (GFP). New bone formation (NBF) in the sutural area was evaluated by µCT and occlusal radiography. In addition, semi-quantitative analyses were performed on histology images to analyse the quality of sutural bone, connective tissue and vascularization. Immunohistochemistry analyses were conducted for osteocalcin and collagen type I proteins. RESULTS: After the 21-day retention period, limited GFP marked cells were detected around the sutural area. Samples treated with BMSCs + PRP had the highest NBF and showed higher expression of collagen type I and osteocalcin. CONCLUSION: Injecting BMSCs + PRP may increase sutural bone density significantly. However, injecting BMSCs or PRP carriers alone did not affect sutural bone density.

Evaluation of the Shear Bond Strength and Antibacterial Activity of Orthodontic Adhesive Containing Silver Nanoparticle, an In-Vitro Study.

This study evaluated the effect of incorporating silver nanoparticles (AgNPs) into conventional orthodontic adhesive on its antibacterial activity and the shear bond strength (SBS) to stainless steel orthodontic brackets. Thirty-four extracted premolars were randomly allocated into two groups (n = 17). Orthodontic adhesive (Transbond XT, 3M Unitek) was blended with AgNPs (50 nm, 0.3% w/w) to form a nano-adhesive. In order to bond stainless steel twin brackets (0.022-inch, American Orthodontics), Transbond XT (n = 17) and nano-adhesive (n = 17) were used in each group, respectively, after acid etching (37% phosphoric acid, 30 s) and rinsing with water (15 s). SBS and the adhesive remnant index (ARI) scores were recorded. Antibacterial activity against Streptococcus mutans in both groups after 24 h and 30 days was assessed (Disc agar diffusion test) and the inhibition zone diameter around each specimen was measured and recorded. Adding AgNPs significantly (p = 0.009) reduced the mean (SD) SBS in the nano-adhesive group [10.51(7.15) MPa] compared to Transbond XT [17.72(10.55) MPa]. The ARI scores on the Transbond XT and nano-adhesive showed no statistically significant difference (p = 0.322). Nano-adhesive with AgNPs showed significant antibacterial activity against Streptococcus mutans at 24 h and 30 days (p < 0.001). In both groups, no significant decline in the zones of inhibition was detected after 30 days (p = 0.907). The findings suggest that SBS decreased after incorporation of AgNPs [0.3% (w/w)], but was still above the recommended SBS of 5.9-7.8 MPa. The nano-adhesive showed significant antibacterial activity which did not change much after 30 days.

Comparison of Single and Multiple Low-Level Laser Applications After Rapid Palatal Expansion on Bone Regeneration in Rats.

Introduction: This study was performed to compare the effects of single and multiple irradiations of low-level laser therapy (LLLT) on bone regeneration in a mid-palatal suture following rapid palatal expansion (RPE). Methods: In this animal study, 40 male Wistar rats underwent RPE for 7 days and were divided into 4 groups including A: single LLLT on day 7, B: Multiple LLLT on days 7, 9, 11, 13 and 15, C: control (no LLLT), and D: sacrificed on day 7. Animals in group D were used to determine the amount of suture expansion. LLLT was done by a diode laser set at an 808 nm wavelength with a useful power output of 100 mW and duration of 0.1 ms. LLLT was applied to three points. After three weeks of retention, the rats were sacrificed and beheaded and the maxilla was evaluated by occlusal radiography, µ-CT, and histomorphometric analyses. A comparison of the mean measurements between the groups was performed using ANOVA and the Tukey post hoc test. Results: Based on occlusal radiography and µCT, bone density in group B was significantly higher than group A and group C (P<0.05). There was no significant difference in bone density between group A and group C (P>0.05). Mean suture width (MSW) in group B was significantly lesser than the control group (P=0.027) while there was no significant difference between MSWnin groups A and B (P=0.116) and groups A and C (P=0.317). Conclusion: It may be concluded that multiple low-power laser irradiation improves bone regeneration after RPE while single irradiation does not have a positive effect.

Effect of mesenchymal stem cells injection and low-level laser therapy on bone formation after rapid maxillary expansion: an animal study.

INTRODUCTION: One of the most common orthodontic problems is maxillary constriction, which is mostly treated by rapid palatal expansion (RPE). However, its high rate of relapse and prolonged retention period have led to some challenges for orthodontists. To encounter these issues, accelerating bone regeneration can provide long-term stability of expanded maxilla. The present study aimed to evaluate the effect of low-level laser therapy (LLLT), bone marrow-derived mesenchymal stem cells (BMSCs) and their combination on promoting bone regeneration of the inter-maxillary suture after RPE in rats. MATERIALS AND METHOD: Total of 60 rats went under RPE treatment. After 7 days, retention period started and interventions (group A, Control (saline); group B, LLLT; group C, BMSCs; group D, LLLT + BMSCs) were performed in the sutural area. After 21 days, radiographic and histological analyses were done. Histological analyses were conducted to evaluate the following criteria of the newly formed bone: the number of osteoblasts, new bone formation, vascularization, connective tissue. Moreover, sutural width was assessed in histologic images. To evaluate bone density at suture area, gray scale and Hounsfield Unit values were measured based on the occlusal radiographic and Micro-Computed topography images respectively. RESULTS: Only in group C and D, osteoblasts and new bone formation were observed in all of the samples. There were no significant differences among the study groups regarding the post-treatment sutural width (P > 0.05). In the radiographic analysis, only group D showed more bone density compared to the control group (P = 0.022). Similarly, in micro-CT analysis, the most bone density was observed in group D which was significantly more than the control group (P = 0.013). CONCLUSION: Our findings suggest that the application of LLLT and BMSCs is the most beneficial approach in accelerating bone regeneration in the inter-maxillary suture.

An Objective Assessment of Orthognathic Surgery Patients.

OBJECTIVES: To retrospectively assess malocclusions, skeletal relationships and the functional needs of orthognathic patients treated in a University teaching hospital. SUBJECTS AND METHODS: This study used clinical records of 100 consecutive patients [51 female, 49 males, mean (SD) age =21.5 (2.71) years] who had orthognathic surgery in a Shahid Beheshti University of Medical Sciences affiliated hospital (9/2014-7/2017). Malocclusion type (incisor classification), sagittal skeletal pattern (ANB angle), index of orthognathic functional treatment need (IOFTN) score, and osteotomy type were recorded. RESULTS: Overall, 66%, 31%, and 3% had Class III, II, and Class I malocclusions, respectively. Similarly, 68% and 32% had Class III and II sagittal skeletal relationships, respectively. Overall, 95% of patients scored IOFTN 4 or 5. The most prevalent IOFTN score were 4.3 (37%), 5.3 (16%), 5.4 (16%), and 4.2 (10%). There were no gender differences (P >0.05) for the distribution of malocclusions, sagittal skeletal relationships, different IOFTN scores, or when IOFTN scores were re-grouped (5, 4, and ≤3). When IOFTN scores were re-grouped (5, 4, and ≤3), they were equally distributed among patients with Class II or III skeletal relationships (P >0.05), but when the authors looked at different malocclusions, there were significant differences in IOFTN score distribution (P = 0.006). The use of genioplasty (4%) or distraction osteogenesis (2%) was limited. Single jaw surgery of either maxilla or mandible was used in 15% and 22% of patients, respectively. About 63% had undergone double-jaw surgery. CONCLUSION: Retrospective assessment using IOFTN identified 95% of patients as having great and very great functional needs, but prospective studies using IOFTN is needed to assess the need for orthognathic surgery. Class III malocclusions and Class III sagittal skeletal relationships were more common in this sample.

Comparative effectiveness of Low Level Laser therapy and Transcutaneous Electric Nerve Stimulation on Temporomandibular Joint Disorders.

Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure analysis of variance (ANOVA) and Bonferroni statistical tests. A P value < 0.05 was considered significant. Results: The decrease in pain (P=0.000), tenderness (P=0.000) and increase in mouth-opening ability (P=0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (P=0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (P=0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less important.

The Effect of An Angiogenic Cytokine on Orthodontically Induced Inflammatory Root Resorption.

OBJECTIVE: Orthodontically induced inflammatory root resorption (OIIRR) is an undesirable sequel of tooth movement after sterile necrosis that takes place in periodontal ligament due to blockage of blood vessels following exertion of orthodontic force. This study sought to assess the effect of an angiogenic cytokine on OIIRR in rat model. MATERIALS AND METHODS: In this experimental animal study, 50 rats were randomly divided into 5 groups of 10 each: E10, E100 and E1000 receiving an injection of 10, 100 and 1000 ng of basic fibroblast growth factor (bFGF), respectively, positive control group (CP) receiving an orthodontic appliance and injection of phosphate buffered saline (PBS) and the negative control group (CN) receiving only the anesthetic agent. A nickel titanium coil spring was placed between the first molar and the incisor on the right side of maxilla. Twenty-one days later, the rats were sacrificed. Histopathological sections were made to assess the number and area of resorption lacunae, number of blood vessels, osteoclasts and Howship's lacunae. Data were statistically analyzed using ANOVA and Tukey's honest significant difference (HSD) test. RESULTS: Number of resorption lacunae and area of resorption lacunae in E1000 (0.97 ± 0.80 and 1. 27 ± 0.01×10(-3), respectively) were significantly lower than in CP (4.17 ± 0.90 and 2.77 ± 0.01×10-3, respectively, P=0.000). Number of blood vessels, osteoclasts and Howship's lacunae were significantly higher in E1000 compared to CP (P<0.05). CONCLUSION: Tooth movement as the outcome of bone remodeling is concomitant with the formation of sterile necrosis in the periodontal ligament following blocked blood supply. Thus, bFGF can significantly decrease the risk of root resorption by providing more oxygen and angiogenesis.

Effect of basic fibroblast growth factor on orthodontic tooth movement in rats.

OBJECTIVE: Basic fibroblast growth factor (bFGF) is a cytokine involved in angiogenesis, tissue remodeling and stimulation of osteoblasts and osteoclasts. The present study assesses the effects of a local injection of bFGF on the rate of orthodontic tooth movement. MATERIALS AND METHODS: : In this laboratory animal study, we randomly divided 50 rats into 5 groups of 10 rats each. Rats received 0.02 cc injections of the following doses of bFGF: group A (10 ng), group B (100 ng) and group C (1000 ng). Group D (positive control) received an orthodontic force and injection of 0.02 cc phosphate buffered saline whereas group E (negative control) received only the anesthetic drug. A nickel titanium spring was bonded to the right maxillary first molar and incisor. After 21 days, the rats were sacrificed and the distance between the first and second right molars was measured by a leaf gauge with 0.05 mm accuracy. ANOVA and Tukey's HSD statistical tests were used for data analysis. RESULTS: The greatest mean value of orthodontic tooth movement was 0.7700 mm observed in group C followed by 0.6633 mm in group B, 0.5333 mm in group A, 0.2550 mm in group D and 0.0217 mm in group E. There was a significantly higher rate of tooth movement in the test groups compared to the control groups (p<0.05). Among the test groups, the rate of tooth movement in group C was significantly higher than group A (p<0.05). Weight changes after the intervention were not significant when compared to the baseline values, with the exception of group E (p>0.05). CONCLUSION: The effect of bFGF on the rate of tooth movement was dose-dependent. Injection of 1000 ng bFGF in rats showed the most efficacy.

The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption.

INTRODUCTION: Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE. METHODS: A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey's Test and Analysis of Variance (ANOVA). RESULTS: All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to 25±1.8 weeks in control group. The data analysis showed that in patients with DTE, laser intervention significantly accelerated tooth eruption (P < 0.05). CONCLUSION: Laser-assisted surgical removal of the fibrous tissue over erupting premolars (DTE) with appropriate irradiation parameters appears to be a promising adjunct to orthodontic treatment for bringing the premolar to the aligned and leveled dental arch.