Iranian Journal of Orthodontics
Volume:1 Issue: 3, Apr 2006

Improvement of clinical signs like pain and mandibular movements' restriction with capturing the natural disc location are among the main purpose of occlusal appliance therapy for the patients affected by internal derangement. The aim of this investigation was to determine the disc location and clinical findings in internal derangement patients, treated by an interocclusal appliance.

A total of 15 patients affected by internal derangement were selected on the basis of defined including and excluding criteria for treatment using a maxillary stabilization appliance. Patients were under detailed assessment in three occasions of before treatment, two and six months after the treatment. This was to determine the disc location in magnetic resonance imaging view and the effect of appliance on clinical findings like joint pain and mandibular movements restrictions. Descriptive statistical analysis and Friedman nonparametric test were used to analyse the data (SPSS Ver. 12.0)

Improvements in clinical findings were observed in all (100%) patients after 2 months from the beginning of treatment and continued to be at 60% rate at the end of treatment. This improvement was found to be statistically significant when compared to other treatment sequences (P<0.001). Disc shape remained unchanged after treatment (23 in normal condition and 7 deformed). In open position, 11 joints were diagnosed as normal, 7 joints with disc dislocation and reduction, 12 joints without reduction before and after treatment while only one joint was added to normal group from the dislocated discs groups with reduction. Statistical analysis did not show any significant difference between disc location before and after treatment.

Stabilization appliance improves clinical findings without disc recapturing. Continuous use of the appliance until six months increase, the treatment success rate in comparison to 2 months use (IJO 2006;1:145-53).

Cleft lip and palate is a social and functionally crippling problem. It is necessary to assess the degree of this problem in our society. The goal of thin study was to assess the number of cleft lip and palate patients in orthodontic patients reporting to Armed Forces institute of Dentistry (AFID), Rawalpindi, from 2001 through 2006.
1118 consecutive patients reporting to AFID were included in the study. 18 were excluded based on inadequate records. Records were evaluated for the presence of clefts, impacted and missing teeth.
1% patients were found to have various kinds of clefts. 72.7% were female and the rest were male. Their mean age was 16.5 years. Bilateral clefts were more common. Reverse overjet and missing maxillary lateral incisors were strongly associated with cleft lip and palate.
Cleft lip and palate is reasonably prevalent in our society. Genetic predisposition and environmental factors are equally important in governing its occurrence. Both these issues have to be considered to reduce the incidence of this problem in a developing country such as ours WO 2006; 1:154-7).

To examine the effect of single jaw surgery (mandibular setback) on the vertical relationships of skeletal class III patients and also examine the relationship between these probable changes and occlusal plane angle.

The measurements were evaluated on the preoperative and postoperative cephalometric radiographs of 33 skeletal class III Patients, that preoperative lateral cephalograms were taken before surgery and after insertion of surgical stabilizing arch wires and the postoperative lateral cephalograms were taken before the starting of postoperative orthodontic treatment. Vertical relationships were measured by the analysis of Legan and Burstone.

The results showed that sagittal correction of mandibular prognathism caused significant reduction of lower anterior facial height (p< 0.001, mean =1.8mm ±1.44mm), and no significant correlation was found between lower anterior facial height change and occlusal plane angle and the amount of setback lonely and with together.

After mandibular setback surgery lower anterior facial height was reduced significantly, but it is not possible to find a significant correlation between lower anterior facial height changes and occlusal plane angle and/or amount of mandibular setback, so no prediction is possible for lower anterior facial height changes after mandibular setback surgery. These issues have to be considered to reduce the incidence of this problem in a developing country such as ours (1.10 2006;1: 158-62).

Lips-Dentition relationships play a special role during smile. Present study compared the relationship of lips and teeth during posed smile in subjects with normal occlusion, class 1 malocclusion and non-extraction treated cases.
20 cases with normal occlusion according to Andrews' and without facial malformation (N), 22 cases with moderate crowding (C 1) and 12 well treated patients without any extraction and facial malformation (T) with the age between 15 — 20 years old were selected. One photograph in rest position and another in posed smiling were taken in standard position. 12 variables on photos were measured by use of a smile mesh. ANOVA and Krukal-wallis tests were used for analysis.
Commissure width and Smile width was significantly greater in group N than groups Cl and T (P<0.001). Upper lip curvature in non-extraction treated group was concave but in others were convex (P<0.022). Inter-canine width in group N was significantly higher than treated patients (P<0.03).
There is a direct relation between anatomic form of lips in rest and in smiling. Orthodontic treatment can cause some changes in lips form during smiling (IJO 2006; 1:163-7).

Application of light cure composites has become very popular in orthodontics. The aim of this study was to compare shear bond strength (SBS) of Ideal Maccoo and Vit L-essence light cure composites in bracket bonding after thermocycling.
100 intact freshly extracted upper first premolars were randomly assigned into four equal groups. In the first and second group Vit L-essence composite was applied to the bracket base and transferred to buccal enamel surface and cured for 40 seconds. In the third and fourth group Ideal Maccoo composite was used for bracket bonding. After 24 hours the teeth in the first and third group were thermocycled between 5 to 55°C and then debonding was performed by Zwick testing machine. The mean shear bond strength of four groups was compared by ANOVA test.
There was no significant difference between Vit L-essence and Ideal Maccoo composite either before or after thermo cycling. SBS also did not differ significantly before and after thermo cycling in each single group.
It was concluded that: 1-Therrnocycling did not affect the SBS of Vit-Lessence and Ideal Maccoo composite in bracket bonding. 2- There was no significant difference in SBS of Vit L-essence and Ideal Maccoo composite either before or after themocycling (DO 2006; 1:168-71).

Open bite is the most difficult malocclusion to treat. Complete knowhow of its frequency is required for an efficient treatment delivery to a community. The main goal of this study was to calculate the frequency of an anterior and posterior open bite in a local setting.
Out of a total sample of 1856 patients reporting to Armed Forces institute of dentistry from 200lthrough 2008, 1800 patients fulfilled the inclusion criteria. Dental records including photographs and casts were observed for the presence of anterior and posterior open bite. The frequency of open bite from the total sample and its percentage with respect to gender and age was calculated.
The frequency of open bite was found to be 5.5%, 73.73% had anterior open bite and 26.26% had posterior open bite. The mean age of patients was 21.6 years. Females were twice as frequently affected as males. Unilateral posterior open bite and Simple anterior open bite were more prevalent.
There is no question that this is one of the most difficult malocclusions to manage and maintain in orthodontics. Its treatment should be primarily etiology oriented and according to our individual requirements so as to prevent the chances of relapse WO 2006; 1:172-5).

A common procedure for the palatally impacted canines specially the deeply impacted ones, is surgical exposure followed by orthodontic treatment. Due to this we intended to evaluate the long-term treatment effect of deeply impacted maxillary canine.

Sixty patients were treated from 1994 to 1999 with deeply impacted maxillary canine. The canine was exposed by closed surgical exposure, the palatal mucoperiosteal flap was reflected, and bone was removed and the flap is repositioned. A hole was made through the crowns and a 0.6mm soft stainless steel was passed through the hole and a loop was made. To apply force to align the tooth in the dental arch, fixed appliances were used with a transpalatal bar and/or headgear to control vertical anchorage. The patients were followed up for three years.

For 12 canines, a definite outcome was recorded which was predominantly successful. From the remaining canines, two were extracted due to ankylosis and two had ultimately an unfavorable alignment in the dental arch.

Closed surgical approach along with "making hole" technique is an appropriate method for the treatment of deeply impacted palatally maxillary canines MO 2006;1:176-83).

Some cphalometric angles change during growth and in accordance with facial height and other 'facial landmarks which make it less reliable for orthodontic diagnosis. The purpose of this study was to find out relationship between Beta Angle and the anterior-posterior position of jaws.
Sixty lateral cephalograms of 16 boys and 44 girls with class I, H or HI malocclusions were evaluated in our study. we traced all of the cephalograms to measure Beta angle and compare these values between different types of malocclusions. Data were annalized by means of T-student statistical test.
Beta angle was 28.5° - 37.5° for class 1, less than 28.5° for class II and more than 37.5° for class III. There was no correlation between t3 angle and facial height.
Beta angle is independent from facial height. Beta Angle has an acceptable specificity and sensitivity for determining the anterior posterior position of Jaws (IJO 2006; 1: 184-7).

To extract or not to extract?! This fundamental decision has spawned some intense debate in orthodontics. Crowding, as a common problem in permanent dentition, is usually handled by extraction and non extraction treatment. It is well established that increase in dental arch length and width during orthodontic treatment tend to return toward pretreatment values after retention. An undocumented criticism of extraction treatment is that it results in narrower dental arches and therefore less attractive smile esthetics.

The main purpose of this study was to examine the dental arch width changes of extraction and non extraction treatment in patients treated in dental faculty of Tehran University of medical science.

This study was performed on pretreatment and post treatment dental casts of 75 patients (36 extraction and 39 non extraction). Arch widths were measured from the cusp tips of the canines and first molars, using a digital caliper.

Multiple regression analysis was used to evaluate the treatment changes in the arch width dimensions. The results show that intercanine arch width in both arches at the end of treatment was not significantly changed neither in extraction nor non extraction treatment. However; intermolar arch width in both arches shows differences between two groups. It increased significant) in non extraction treatment, and decreased in extraction samples.

The results of this study indicate that intercanine arch width has no significant relationship with the type of treatment, but intermolar arch width shows statistically significant difference between two groups. We can conclude that constricted arch widths are not a usual outcome of extraction treatment, as there is no significant difference between post treatment intercanine arch width in two types x of treatment (DO 2006;1:187-93).

Being aware of the active and reactive forces and moments in an applied force system helps minimizing side effects and informing patients of future happenings. Wire bends are still used in clinical orthodontics in different ways.
Three models were designed in SolidWorks 2006. A step bend of 0.5 mm, a model of two central incisors with their supporting structures, and two blocks with a space and a wire with a combination of two step bends to modify the tooth angulation. Then the models were transferred to ANSYS Workbench Ver. 11.0 for calculations. Different positions of a step bend and the force systems produced by them were assessed.
A gradual decrease of force produced by the step bend between 316 and 308 grams was shown to exist in central step bend position and the extreme one. The moment followed almost the same pattern starting from 15.125 N.mm in center bend position to 14.135 N.mm in its extreme position. In combined step bend model, extrusive/ lingualized movment in one side and intrusive/ labialized in the other side and tipping of the crowns in one and the apices to other side was also shown.
Step bend is not sensitive to its position and almost the same force system is produced in different bend positions (IJO 2006;1: 194-7).

This article describes various aspects of risks and complications, commonly encountered in orthodontic treatment as a result of its materials, and also describes ways to minimize them in the course of orthodontic treatment. Although, like many other treatments, it has fundamental risks and complications. Thus, it is important to control the risks during and after orthodontic treatment (IJO 2006;1:198-202).

Impaction of the lower second molar is not a common problem (0.03%), but it is very challenging for orthodontists. Unilateral mandibular second molar impaction is the most popular form of second molar impactions. The etiology of which is related to some disturbances in physiological mandibular growth and tooth development. Other factors have been cited for this problem is iatrogenic such as space gaining procedures in mixed dentition. Treatment options depend on degree of tooth inclination, the position of third molar and desired type of tooth movement. Advantages of impacted molar uprighting arc functional, periodontal and restorative. In this case report, treatment of partially impacted second molars in a 12 year — old girl with class I malocclusion is presented. Uprighting of both second molars was performed in two stages. It was concluded that using continuous stainless steel wire with T-loop and gable bend is an effective method for correction of second molar inclination with the least risk of molar extrusion.