ABSTRACT
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
ABSTRACT
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. 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]. 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]. 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
ABSTRACT
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. 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. 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]. The effect of bFGF on the rate of tooth movement was dose-dependent. Injection of 1000 ng bFGF in rats showed the most efficacy