palatal expanson in orthodontics /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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palatal expanson in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. A COMPARISON OF DENTAL AND DENTO- ALVEOLAR CHANGES BETWEEN RAPID PALATAL EXPANSION AND NICKEL-TITANIUM PALATAL EXPANSION APPLIANCES www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. INTRODUCTION • Skeletal expansion involves separating the right and the left maxillary halves at the mid palatal suture. • Dental expansion results from buccal tipping of the maxillary posterior teeth. • The proportion of skeletal and dental movement is dependent on the rate of expansion and the age of the patient during treatment. www.indiandentalacademy.com
  3. 3. • The goal of palatal expansion maximize skeletal movement and minimize dental movement, while allowing for physiologic adjustment of the suture during separation. • Expansion appliances can be classified as rapid or slow. Rapid palatal expansion appliances produce large forces at the sutural site over a short period. • Slow expansion appliance produce slow forces over long period of time. www.indiandentalacademy.com
  4. 4. • In 1993,Arndt developed a tandem-loop nickel- titanium temperature activated palatal expander with the ability to produce light, continuous pressure on the midpalatal suture. • The objective of this study was to compare the maxillary dental and dentoalveolar changes between RPE and NiTi palatal expansion appliances. Specifically, the amount of mid palatal suture separation, maxillary alveolar tipping, maxillary first molar tipping, maxillary molar rotation and palatal depth changes in response to treatment were quantified.. www.indiandentalacademy.com
  5. 5. MATERIALS AND METHODS • The study comprised 12 patients treated with RPE appliances and 13 patients treated with NiTi palatal expansion appliances at the West Virginia University Department of Orthodontics. • Criteria for patient selection include patients of mixed or early permanent dentition who required palatal expansion as part of their comprehensive orthodontic treatment. www.indiandentalacademy.com
  6. 6. • The RPE group comprise 6 males and 6 females with an average age of 11.1 years. • 8 of the 12 patient had either a unilateral or a bilateral posterior cross bite at the start of the treatment. • The average treatment time was 127 days. • The NITI expansion group comprise 3 males and 10 females with an average age of 9.4 years. • 11 of the 13 patient had a unilateral or bilateral posterior cross bite at the start of the treatment. • The average treatment time for this group was 153 days. www.indiandentalacademy.com
  7. 7. • The RPE appliances was a tooth borne appliance that could be bonded or banded to the maxillary anchor teeth. • Expansion was carried by means of mid- palatal jack-screw. Patient were instructed to activate the jack-screw 2 times/day{0.5mm}. • expansion was considered adequate when the occlusal aspect of maxillary lingual cusp of the permanent first molars or the primary second molars contacted the occlusal aspect of the mandibular facial cusp of either the permanent first molars of the primary second molars. www.indiandentalacademy.com
  8. 8. • The appliance was left in place for approximately 3 months after active expansion. • The NiTi expander was a tandem-loop temperature activated expansion appliance consisted of 2 tandem, temperature – sensitive, 0.035 inch diameter NiTi transpalatal loops that were connected bilaterally to the lingual sheaths of the maxillary bands. • Anteriorly, a 0.032 inch diameter stainless steel wire formed a helical loop finger spring designed for lateral expansion in the canine and premolars region.www.indiandentalacademy.com
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  10. 10. • The appliance manufactured in 8 sizes in 3- mm increments. • The proper size was selected by measuring the inter molar width on the pretreatment study casts from the maxillary molar lingual groove at the gingiva, to the opposite lingual groove, and then adding 3 to 4mm. • for the placement of appliance, the NiTi trans palatal loops were sprayed with a tetra fluroethane refrigerant. www.indiandentalacademy.com
  11. 11. STUDY CAST EVALUATION • Study cast were taken before and after treatment to analyze the difference between the appliance in palatal width changes, maxillary alveolar tipping, maxillary molar tipping, maxillary molar rotation and palatal depth changes. • Palatal width: transverse palatal contour tracing of the casts were made by using a symmetrograph, as described by Korkhaus. www.indiandentalacademy.com
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  13. 13. • A Symmetrograph is a specialized form of a pantograph used to copy a shape, in this case the palatal contour of the study model to any desired scale. • To compare palatal width change, the pretreatment cast was secured on the rotating plate form so that the median palatal raphe was parallel to the recording plate and occlusal plane was parallel to the base . • The median palatal raphe was traced on to the recording plate and this tracing later used to orient the post treatment cast. www.indiandentalacademy.com
  14. 14. • The pretreatment then rotated 900 so that the median palatal raphe was perpendicular to the recording plate. • Once the cast has been rotated, a distinct palatal rugae, point A was located. A perpendicular line was projected from point A to the median palatal raphe. The point of intersection was referred as point B. • The next another line was projected to connect the lowest contour of the lingual gingival margin of the first molar. Its intersection with the median palatal raphe was referred to as point C. www.indiandentalacademy.com
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  16. 16. • The post treatment cast was then placed on the rotating platform so that its median palatal raphe was coincident with the median palatal raphe tracing of the pretreatment cast. • Once these were coincident, the post treatment cast was rotated 900 and point A and point B were located. • The pretreatment and post treatment tracing were then superimposed on the horizontal palatal shelves and at the curvature joining the left alveolar process and palatal shelf. • The difference between the 2 raphes A was the amount of palatal width change to the right. The same procedure was repeated on the right side thus the difference between the 2 raphes B was the amount of palatal width change to the left.www.indiandentalacademy.com
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  18. 18. • Maxillary alveolar tipping. • A line was drawn from the midpoint of the curve of the junction of the alveolar process and tooth to the midpoint of the curve of the junction of the alveolar process and the palatal shelf. • The pretreatment and the post treatment tracing were then superimposed on the lines representing the left alveolus. • The angle formed between the lines on the right side (A) indicate the total amount of alveolar tipping in degree. www.indiandentalacademy.com
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  20. 20. • Maxillary molar rotations. • The polyvinylsiloxane impression putty caps were placed on maxillary first molars on pre treatment dental casts to evaluate the amount of molar rotations. • While the putty was still soft the orthodontic wire (0.040 inch) was inserted into the putty of each first molar so that the wires were parallel to the occlusion plane and intersected at 45 degree angle when viewed from directly above the cast. • A photograph was taken from above the cast with a 200 mm lens at a distance of 175 cm to minimize the distortion of the wire. www.indiandentalacademy.com
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  22. 22. • The angle formed on the post treatment cast B minus the angle formed on the pre treatment cast A was then a measurement of the amount of molar rotation. • Maxillary molar tipping. • Polyvinylsiloxane impression putty caps were placed on maxillary first molars on the pre treatment dental cast to evaluate amount of molar tipping. www.indiandentalacademy.com
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  24. 24. • Palatal depth. • Palatal depth changes were measured by using a square sheet of hard clear acrylic that extended beyond the teeth. • Acrylic was placed on the occlusal surface of the cast so that it contacted the most prominent cusp of the first molar bilaterally and the first contact mesially. • The wire was then extended until it touches the palate, and the measurement was recorded in mm. www.indiandentalacademy.com
  25. 25. • Radiographic evaluation • Maxillary occlusal radiographs were obtained before treatment and 2 weeks after active expansion. • The radiography was performed with the maxillary occlusal plane parallel to the floor and the x- ray cone positioned at a 60o angle to the film and parallel to the facial midline. • Four orthodontic faculty members judged the patients pretreatment and post treatment radiographs for evidence of sutural opening. www.indiandentalacademy.com
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  27. 27. STATISTICAL METHODS • Paired t tests were used to asses significant changes before and after treatment. • The correlation between the measurement changes in the 2 expansion groups was tested by using a matrix of the Pearson correlation coefficient. www.indiandentalacademy.com
  28. 28. RESULTS • Treatment changes in RPE group. Significant increases were found in palatal width (1.41mm) , intermolar width (4.76mm), alveolar tipping (5.08o) and molar tipping (6.08o) no significant changes were found in palatal depth (-0.07) and molar rotation (1.58o). The ratio of palatal width to the intermolar width was found to be 0.28. www.indiandentalacademy.com
  29. 29. • Treatment changes in NiTi expansion group. Significant increase were found in palatal width (0.99mm), intermolar width (6.26mm), alveolar tipping (6.61o), molar rotation (26.61o) and molar tipping (11.69o) no significant changes were found in palatal depth (-0.04). The ratio of palatal width to intermolar width was found to be 0.016. www.indiandentalacademy.com
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  34. 34. CONCLUSIONS 1) Both the RPE and the NiTi expanders are capable of expanding the maxillary dentition and alveolar and are equally capable of correcting posterior cross bites. 2) Stepwise multiple regression analysis showed that alveolar tipping, palatal width change, and molar tipping are the best predictors for intermolar width change in the RPE group. www.indiandentalacademy.com
  35. 35. 3) Radiographic evidence of midpalatal suture separation was found to be less obvious in the NiTi than in the RPE group. 4) No correlation was found between age and the amount of dentoalveolar expansion in either group. 5) The RPE appliance widened the palate more reliably, whereas the NiTi appliance tipped the molars buccaly to a greater extent and caused more distal molar rotation. www.indiandentalacademy.com
  36. 36. CRITICS • In the RPE group, the amount of appliance activation varied from patient to patient, depending on the transverse discrepancies and the operators. • In the NiTi group the amount of activation was performed according to manufacture’s direction. • Another limitation of this study is the sample size and the inability to match the age and gender of the 2 sample. www.indiandentalacademy.com
  37. 37. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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