ABSTRACT
Objective: Root resorption is a complication of orthodontic treatment and till date, there is a dearth of information regarding this issue. The aim of this study was to determine whether the expression of transforming growth factor-beta 1 [TGF-beta 1, an inflammatory cytokine] is related to orthodontic force. Moreover, if associated, the expression level may be helpful in differential diagnosis, control and ultimate treatment of the disease
Materials and Methods: In this experimental study, a total of 24 eight-week-old male Wistar rats were selected randomly. On day 0, an orthodontic appliance, which consisted of a closed coil spring, was ligated to the upper right first molar and incisor. The upper left first molar in these animals was not placed under orthodontic force, thus serving as the control group. On day 21, after anesthesia, the animals were sacrificed. The rats were then divided into two equal groups where the first group was subjected to histological evaluation and the second group to reverse transcriptase-polymerase chain reaction [RT-PCR]. Orthodontic tooth movement was measured in both groups to determine the influence of the applied force
Results: Statistical analysis of data showed a significant root resorption between the experimental group and control group [P<0.05], however, there was no significant difference in the expression level of the inflammatory cytokine, TGF-beta 1
Conclusion: Based on the findings of this study, we suggest that there is a direct relationship between orthodontic force and orthodontic induced inflammatory root resorption. In addition, no relationship is likely to exist between root resorption and TGF-beta 1 expression in the resorptive lacunae
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
Statement of the Problem: Root resorption [RR] after orthodontic tooth movement [OTM] is known as a multifactorial complication of orthodontic treatments. Hormonal deficiencies and their effect on bone turnover are reported to have influences on the rate of tooth movement and root resorption
Purpose: This study was designed to evaluate the effect of female and male steroid sex hormones on tooth movement and root resorption
Materials and Method: Orthodontic appliances were placed on the right maxillary first molars of 10 ovariectomized female and 10 orchiectomized male Wistar rats as experimental groups and 10 female and 10 male healthy Wistar rats as control groups. NiTi closed-coil springs [9mm, Medium, 011"×.030", Ortho Technology[registered sign]; Tampa, Florida] were placed between the right incisors and the first right maxillary molars to induce tipping movement in the first molars with the application of a 60g force. After 21 days, the rats were sacrificed and tooth movement was measured by using a digital caliper [Guanglu, China]. Orthodontic induced root resorption [OIRR] was assessed by histomorphometric analysis after hematoxylin and eosin staining of sections of the mesial root
Results: The rate of tooth movement was significantly higher in all female rats, with the root resorption being lower in the experimental group. The rate of tooth movement in experimental male rats was significantly higher than the control group [p= 0.001] and the rate of root resorption was significantly lower in the experimental group [p= 0.001]
Conclusion: It seems that alterations in plasma levels of estrogen, progesterone, and testosterone hormones can influence the rate of OTM and RR. The acceleration in tooth movement increased OTM and decreased RR
ABSTRACT
Statement of the Problem: A major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement [OTM]
Purpose: The aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin E2, and calcium on orthodontic tooth movement and root resorption in rats
Materials and Method: Sixty four male Wistar rats were randomly divided into 8 groups of eight rats each: 1- 20micro g/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance. 2- 0.1 ml of 1 mg/ml prostaglandin E2 was injected submucosally. 3- 10% [200 mg/kg] calcium gluconate was injected. 4- Prostaglandin E2 was injected submucosally and 10% calcium was injected intraperitoneally. 5- Thyroxine was injected intraperitoneally and prostaglandin E2 was injected submucosally. 6- 20micro g/kg thyroxine with calcium was injected. 7- Prostaglandin E2 was injected submucosally with calcium and thyroxine. 8- Distilled water was used in control group. The orthodontic appliances comprised of a NiTi closed coil were posteriorly connected to the right first molar and anteriorly to the upper right incisor. OTM was measured with a feeler gauge. The mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. The Data were analyzed by one-way ANOVA and Student-Newman-Keuls test
Results: The highest mean OTM was observed in the thyroxine and prostaglandin E2 group [Mean +/- SD = 0.7375 +/- 0.1359 mm] that was significantly different [p< 0.05]. A significant difference [p< 0.05] in root resorption was observed between the prostaglandin E2 [0.0192 +/- 0.0198 mm[2]] and the other groups
Conclusion: It seems that the combination of thyroxine and prostaglandin E2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats
ABSTRACT
Low-Level Laser Therapy [LLLT] provides several benefits for patients receiving orthodontic treatment. According to some literatures, Orthodontic Tooth Movement [OTM] can be enhanced but some investigators have reported contradictory results. This article reviews the literature regarding the different aspects of the use of LLLT on OTM and its alterations. The general data regarding the study design, sample size, wavelength [nm], power [mW], and duration were extracted and recorded independently. Electronic databases of PubMed and ScienceDirect from January 2009 to August 2014 were searched. Also Google Scholar and grey literature was searched for relevant references. Some investigators found that the amount of tooth movement in the Low-Energy Laser Irradiation [LELI] group was significantly greater than in the non-irradiation group by the end of the experimental period. Low-level laser irradiation accelerates the bone remodeling process by stimulating osteoblastic and osteoclastic cell proliferation and function during orthodontic tooth movement. But some researchers have reported that no statistical differences in the mean rate of tooth movement were noted between low energy and high energy experimental sides and their controls. Some evidence shows that low-level laser irradiation accelerates the bone remodeling process and some evidence shows that LLLT has not effect on OTM. In some investigations no statistical differences in the mean rate of tooth movement can be seen between low energy and high energy experimental sides and their controls. It has been shown by authors that laser irradiation can reduce the amount of OTM and a clinical usage for the inhibitory role of low level laser irradiation is enforcing the anchorage unit
Subject(s)
Low-Level Light Therapy , OrthodonticsABSTRACT
Orthodontically induced inflammatory root resorption [OIIRR] is considered to be an important sequel associated with orthodontic tooth movement [OTM]. OTM after Socket preservation enhances the periodontal condition before orthodontic space closure. The purpose of this study is to investigate the histologic effects of NanoBone[R], a new highly nonsintered porous nano-crystalline hydroxyapatite bone on root resorption following OTM. This experimental study was conducted on four male dogs. In each dog, four defects were created at the mesial aspects of the maxillary and mandibular first premolars. The defects were filled with NanoBone[R]. We used the NiTi closed coil for mesial movement of the first premolar tooth. When the experimental teeth moved approximately halfway into the defects, after two months, the animals were sacrificed and we harvested the area of interest. The first premolar root and adjacent tissues were histologically evaluated. The three-way ANOVA statistical test was used for comparison. The mean root resorption in the synthetic bone substitute group was 22.87 +/- 11.25×10[-4] mm[2] in the maxilla and 21.41 +/- 11.25×10[-4] mm[2] in the mandible. Statistically, there was no significant difference compared to the control group [p>0.05]. The use of a substitution graft in the nano particle has some positive effects in accessing healthy periodontal tissue following orthodontic procedures without significant influence on root resorption [RR]. Histological evaluation in the present study showed osteoblastic activity and remodeling environment of nanoparticles in NanoBone[R]
Subject(s)
Animals , Nanoparticles , Tooth Socket , Root Resorption , Tooth Movement Techniques , Orthodontics , Inflammation , DogsABSTRACT
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
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
Dentine hypersensitivity [DH] is characterized by a short sharp pain arising from the exposed dentine, in response to a thermal, evaporative, tactile, osmotic or chemical stimulus. The aim of this study was to evaluate the efficacy of Nd:YAG laser therapy and desensitizing gel [Sensikin[Registered], Laboratorios Kin S.A., Barcelona, Spain] in treatment of dentine hypersensitivity. A total of 20 patients with at least 6 hypersensitive teeth were selected and divided randomly into three groups: Nd:YAG laser [10 HZ, 1W, 60 S, two times] treated group, Sensikin[Registered] treated group and a control group. Subjects were asked to apply the gel at home for the next week and 3 times a day as they were instructed. Assessment of the pain was performed by visual analyzing scale [VAS] after stimulation of the teeth by compressed air at 6 intervals: before treatment, immediately after treatment, one week, one, three and six months later. The data obtained were analyzed using the SPSS software, one way ANOVA and repeated measurement ANOVA tests. VAS scores did not show any significant differences between the three groups prior to treatment [P value>0.05], but in all groups after treatment VAS scores differed significantly in comparison to VAS scores before treatment [Pvalue<0.05]. This statistically significant difference in the control group demonstrated a placebo effect. However, the efficacy between the three groups was not significantly different. An overall comparison indicated no significant differences at various time intervals. Nd:YAG laser and desensitizing gel effectively reduce DH. However, we found no significant statistical differences between these two groups compared with the control group
ABSTRACT
The relationship between IQ score and malocclusion is a subject that has been the focus of attention in the field of orthodontics. The present study aimed at determining the IQ score of patients with dentoskeletal malocclusions presenting to the Orthodontic Department of Shahid Beheshti Dental School during 2008-2009. This descriptive cross-sectional study was conducted on 160 patients aged 12-18 yrs. who were receiving orthodontic treatment. A questionnaire was designed containing 3 sections of demographic characteristics, general information and orthodontic treatment. The questionnaire was completed by the patient and senior dental students and patients were asked to take the Cattell Culture Fair III IQ test on the computer and the obtained IQ score was recorded. Data were analyzed using linear regression analysis. The mean IQ score of the understudy population was 98 +/- 16. IQ score had a significant correlation with level of education [P<0.001], age [P<0.001] and socioeconomic status [P<0.001]. However, type of skeletal malocclusion and facial growth pattern were not correlated with the IQ score. The obtained results showed no association between type of skeletal malocclusion or facial growth pattern and the IQ score
ABSTRACT
Corticotomy-facilitated orthodontics provides a means for rapidly moving teeth purportedly with little damaging effects to the periodontium and with greatly reduced treatment time. The aim of this study was to enhance the orthodontic tooth movement by reducing the cortical bone layer [resistant to bone re-sorption relative to spongious bone] following Erbium, Chromium doped Yttrium Scandium Gallium Garnet [Er-Cr: YSGG] laser irradiation, without reflection of surgical soft tissue flap. In the present experimental study, 8 New Zealand Male rabbits were the samples for the research. The right first premolar of each rabbit [experiment group] underwent treatment for mesial movement with 75 gram of orthodontic force by using closed Ni-Ti coil spring [Dentaurum [R]]. Coil spring was fixed in the cervical region of first premolars by means of ligature wire and No-Mix composite [Dentaurum[R]] and also activated to the cervical site of incisors. The left first premolars of the subjects were considered as the control group. Laser corticotomy was performed in anesthetized rabbits. Samples were sacrificed for determination of tooth movement after initiating premolar protraction on the 21[th] day. The amount of orthodontic tooth movement was assessed by using a metal feeler gauge with the precision of 0.01 mm, between mesial surface of the second premolars and distal surfaces of the first premolars. The statistical package of SPSS [Kolmogorov - Smirnov and ANOVA test] was used for analytical evaluation of the measurements. The amount of orthodontic tooth movement in the experimental group [mean=1.653 +/- 0.34 mm] was significantly [p<0.001] greater than that of the control group [mean=0.936 +/- 0.28 mm]. The innovated laser assisted corticotomies enhanced the rate of orthodontic tooth movement on the intervention side, significantly [p<0.001]. The innovated method of laser assisted flapless corticotomy is a useful procedure for reducing treatment time and damage to periodontium. It also eliminates the necessity of more invasive intervention of flap surgery
Subject(s)
Male , Animals, Laboratory , Orthodontics , Laser Therapy , Treatment Outcome , RabbitsABSTRACT
The purpose of this study was to investigate the histologic interaction between two different allografts and first premolar root; following orthodontic tooth movement. Sample consisted of four male dogs. In each animal, four defects were created at the mesial aspects of the maxillary and mandibular first permanent premolars. The defects were filled with DFDBA or FDBA equally. NiTi closed coil with 150 gr force was used for mesial movement of the first premolar. When the experimental teeth were had been moved about halfway into the defect spaces i.e.nine weeks, the animals were sacrificed and the area of interest were harvested. The first premolar root and adjacent tissues were histologically evaluated. Tooth movements were analyzed using paired t test. The findings demonstrated that it was possible to move a tooth into a defect, filled with DFDBA or FDBA with the same rate of tooth movement. Mean tooth movement in DFDBA and FDBA was 2.6 +/- 0.11 mm in DFDBA and 2.4 +/- 0.12 mm in FDBA. Apical root resorption occurred on the pressure sides in both groups. These findings indicate that FDBA and DFDBA could be a biocompatible bone substitute into bone defects subjected to orthodontic tooth movement
Subject(s)
Male , Animals , Orthodontics , Transplantation, HomologousABSTRACT
To determine the effect of orthodontic tooth movement on the expression of interleukin-1beta mRNAin rats using RT-PCR. Sample consisted of eighteen 8-week-old male Wistar rats. The right maxillary first molar of each animal was protracted using an orthodontic protraction appliance. The left maxillary first molar received no treatment and was assigned as the control group. On day 21, all rats were sacrifice and divided in two equal groups. The first group, group [A], was histologically evaluated for the presence and size of potential resorptive lacunae. The second group, group [B], was investigated using RT-PCR in order to determine IL-1beta mRNA expression. Measurements revealed that the mean tooth movement was 0.23 mm in group A and 0.24 mm in group B. The mean depth of the resorptive lacunae was 0.17*10[-11] mm[2] in the control group and 4.9x10[-11] mm[2] in the intervention group [control group: left maxillary first molars; right maxillary first molars were divided to group A and B, histologic study of group A assures the existence of resorptive lacunae and its extent relative to control group]. The difference between the two groups was statistically significant [p<0.05]. The RT-PCR evaluation showed no significant differences in IL-1beta mRNA expressions of resorptive lacunae between the treated and untreated groups. Although interleukinl-beta is the most potent stimulator of bone resorption and mediator of inflammatory response, the present study showed that the IL-1 beta mRNA was not expressed more significantly in root resorption lacunae of the treated molars relative to the control group
ABSTRACT
To determine efficacy of low level laser therapy for clicking temporomandibular joint [TMJ] with a diode laser following orthodontic treatment. Performance of LLLT with a diode laser for temporomandibular clicking and postoperative findings were evaluated in a case of an orthodontic patient following the termination of treatment. Patient had a history of severe clicking before initiation of treatment protocol. Low level diode laser [wave length 808 nm, power 0.7 watt, Time 60 seconds], applied for the purpose of relieving the signs. During the process of intervention and establishing the proper dental occlusion sign of temporomandibular joint dysfunction i.e. clicking reduced significantly [p<0.05] but remained at the lowest level from the perspective of frequency and severity index. Patient had no sign and symptom at the end of treatment. Clicking was reemerged in the retention period, i.e. after six months. Clinical signs disappeared immediately after the application of laser once [p<0.05] with no recurrence after four months follow up. Low level laser therapy serves as an adjuvant to orthodontic treatment while establishing the proper occlusion of stomatognathic system has pivotal role in function and stability of outcome
ABSTRACT
Controversial results have been reported when organic acids, ultrasonic instruments and laser techniques were used to remove smear layer in endodontic treatments. The aim of this study was to evaluate the effect of removing debris and smear layer by Er,Cr:YSGG laser irradiation on the apical leakage of retrograde cavities. In this ex vivo study, 24 extracted mandibular single-rooted teeth were selected and instrumented up to K-file size #35. Approximately 3 mm of root apices were dissected perpendicular to the root's long axis. Retrograde cavities with 3 mm depth were prepared and the teeth were randomly assigned to two groups. In one group, the retrograde cavities were filled with amalgam and in the other group, the dentinal surface of the retrograde cavities were lased with Er,Cr:YSGG laser [2W, 15 seconds, G4 tip]. The cavities were filled with amalgam; all tooth surfaces except for dissected outsides were covered with blue wax. Then the teeth were immersed in 2% methylene blue dye for 48 hours. The amount of dye penetration into sagittal sections was measured by stereomicroscope at _20 magnification by two independent observers who were blinded to the experiment. Data were statistically analyzed using student t-test. This study demonstrated that dye penetration was 0.8 mm [ +/- 0.53] in the lased and 0.97 mm [ +/- 0.54] in the non-lased group. It showed that, Er,Cr:YSGG laser can remove the debris and smear layer and consequently reduces the amount of dye penetration, although, the difference between the two groups was not statistically significant. This study showed that dye penetration was less in lased group because of the better seal of the dissected surface due to the better removal of the debris and smear layer by laser; further investigations are recommended in this field