Initial Intrusion of the
Molars in the Treatment of
Anterior Open Bite
Malocclusions in Growing
Patients
www.indiandentala...
INTRODUCTION
 Openbite can be related to skeletal, dental, and soft tissue
effects and generally contain a combination of...
 steep mandibular plane, obtuse gonial angle, increased
lower face height, and counterclockwise rotation of the
palatal p...
 control of the vertical dimension is considered the
most important factor in the treatment of open bite
malocclusions.
N...
 The purpose of this study is to present the Molar
Intruder (MI) appliance, which can be used to
intrude molar in the lat...
MATERIALS AND METHODS
 14 patients (8 girls and 6 boys)
 age of 10 years and 7 months (range 9.2 to 12.4 years)
(late mi...
Appliance construction
 working models were obtained from the patient.
 A construction bite exceeding the freeway space ...
 Adams clasps (0.7-mm s.s.wire) for the maxillary premolars or
maxillary first molars if only the second molars were to b...
Clinical management
 MI was adjusted in the mouth in a passive state, and then the intrusion
springs were activated.
 Fo...
Cephalometric analysis
 17 landmarks and 21 parameters were used in the study.
www.indiandentalacademy.com
 Treatment effects were determined by Superimposing the
lateral cephalograms.
1 patient 2
www.indiandentalacademy.com
BEFORE
1 PATIENT 2
AFTER
www.indiandentalacademy.com
RESULTS
www.indiandentalacademy.com
The changes are
 SNB > increased by 1.57°
 ANB > decreased by 1.29°
 Y axis > decreased by 1.36°
 SN/MP angle > decrea...
DISCUSSION
 Adult skeletal open bite is ideally corrected with a combination of
orthodontics and orthognathic surgerybeca...
>In this study, the intrusive force for molars ranged between
110gm and 180 gm, depending on whether only one or two
molar...
It is difficult to use the upper springs of the MI with expansion
screws. However, they can be used if precise readjustmen...
 Radiograph showed minimal root resorption in the molars(3 patients).
The resorption rate was minimal.
 The long-term ef...
CONCLUSIONS
 MI is effective in intruding the molars and in reducing the
anterior openbite.
 MI is also effective in sel...
thank y u
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Jc 10 /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.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Jc 10 /certified fixed orthodontic courses by Indian dental academy

  1. 1. Initial Intrusion of the Molars in the Treatment of Anterior Open Bite Malocclusions in Growing Patients www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. INTRODUCTION  Openbite can be related to skeletal, dental, and soft tissue effects and generally contain a combination of these factors. Proffit WR. Contemp Orthod. St Louis, Mo: CV Mosby; 1986.  In open-bite cases of skeletal origin, the factors responsible for the malocclusion cannot be identified easily. Proffit WR. Contemp Orthod. St Louis, Mo: CV Mosby; 1986. Noar JH, Am J Orthod Dentofacial Orthop. 1996.  Skeletal openbites show more molar and incisor eruption than dental openbites, and the excessive dentoalveolar heights increase the severity of the malocclusion. Cangialosi T. Am J Orthod. 1984 Worms F, Am J Orthod. 1971 www.indiandentalacademy.com
  3. 3.  steep mandibular plane, obtuse gonial angle, increased lower face height, and counterclockwise rotation of the palatal plane are parameters of skeletal anterior openbites.  Parameters of dentoalveolar openbites are divergent max. & man. occlusal planes, mesial inclination of posterior teeth, and lack of a normal curve of Spee in the lower arch.  Subtelny JD, Am J Orthod. 1964 Nahoum HI, Am J Orthod. 1972 Fields HW, Am J Orthod Dentofacial Orthop. 1984 Ellis E, Am J Orthod Dentofacial Orthop. 1984 Ellis E, J Oral Maxillofac Surg. 1985 Kim YH. Angle Orthod. 1987; 57:290–321 Dung DJ. Am J Orthod Dentofacial Orthop. 1988  Treatment of patients with openbite must be performed early to be successful. Otherwise the opportunity for growth modification could be lost & surgical correction as the only possible treatment. www.indiandentalacademy.com
  4. 4.  control of the vertical dimension is considered the most important factor in the treatment of open bite malocclusions. Nahoum HI. Am J Orthod. 1975 Lavergne J. Angle Orthod. 1976 Horn AJ. Am J Orthod Dentofacial Orthop. 1992 English JD. Am J Orthod Dentofacial Orthop. 2001  Various treatment modalities have been proposed for the correction of anterior openbites. Headgear, vertical-pull chincups, vertical elastics, functional appliances, posterior bite-blocks, tongue cribs, transpalatal arches, posterior magnets, multiloop edgewise archwires, miniplate anchorage, orthodontic treatment and orthognathic surgery www.indiandentalacademy.com
  5. 5.  The purpose of this study is to present the Molar Intruder (MI) appliance, which can be used to intrude molar in the late mixed or early permanent dentition and to evaluate the treatment effects of MI. www.indiandentalacademy.com
  6. 6. MATERIALS AND METHODS  14 patients (8 girls and 6 boys)  age of 10 years and 7 months (range 9.2 to 12.4 years) (late mixed or early permanent dentition)  hyperdivergent phenotype. (mandibular plane angle greater than 35°)  anterior openbite (only the molars in occlusion)  adequate transverse dimension in the maxillary dental arch.  Sex and type of malocclusion were not considered in patient selection. www.indiandentalacademy.com
  7. 7. Appliance construction  working models were obtained from the patient.  A construction bite exceeding the freeway space by two mm was taken using wax rims, and the rim was transferred to the working models.  The working models were mounted on a fixator,  Buccal undercuts where clasps were planned were scraped (0.5 mm) with a spatula for extra retention. www.indiandentalacademy.com
  8. 8.  Adams clasps (0.7-mm s.s.wire) for the maxillary premolars or maxillary first molars if only the second molars were to be intruded.  Eyelet clasps (0.7 mm s.s. wire) were incorporated to reinforce the retention of the appliance.  Molar intrusion spring (0.7-mm s.s. wire) >Design of the springs was altered if the second molars were erupted  Acrilization and polishing . www.indiandentalacademy.com
  9. 9. Clinical management  MI was adjusted in the mouth in a passive state, and then the intrusion springs were activated.  Force 1st molar - 110gm 1st & 2nd molar - 180 gm  Patient was instructed to wear the appliance all day except during meals.  Patients were called at three-week intervals to reactivate the springs.  The average treatment time with the MI was five months. After the appliance was removed, orthodontic treatments were carried out with edgewise mechanics www.indiandentalacademy.com
  10. 10. Cephalometric analysis  17 landmarks and 21 parameters were used in the study. www.indiandentalacademy.com
  11. 11.  Treatment effects were determined by Superimposing the lateral cephalograms. 1 patient 2 www.indiandentalacademy.com
  12. 12. BEFORE 1 PATIENT 2 AFTER www.indiandentalacademy.com
  13. 13. RESULTS www.indiandentalacademy.com
  14. 14. The changes are  SNB > increased by 1.57°  ANB > decreased by 1.29°  Y axis > decreased by 1.36°  SN/MP angle > decreased by 1.57°  gonial angle > decreased by 1.50°  NV-Pog distance > decreased by 1.21 mm.  anterior face height > decreased by 1.86 mm  ramus length > increased by 0.46 mm.  posterior facial height/anterior facial height ratio > increase of 2.25%  U6-FH distance > decreased by 1.86 mm  L6-MP distance > decreased by 1.04 mm.  U1-FH distance > increased by 0.54 mm  U1/SN angle > increased by 1.46°  occlusal plane angle > decreased by 2.25°  overbite > increased by 4.00 mm  mandibular sulcus contour > decreased by 3.57 mm www.indiandentalacademy.com
  15. 15. DISCUSSION  Adult skeletal open bite is ideally corrected with a combination of orthodontics and orthognathic surgerybecause the relapse after surgery is usually less than that seen with nonsurgical treatment. Bell WH. J Oral Surg. 1975 Denison TF, Angle Orthod. 1989  early treatment of hyperdivergent cases with anterior openbites not only eliminates the risks associated with orthognathic surgery but also improves a child's self-esteem by improving the appearance. English JD. Am J Orthod Dentofacial Orthop. 2001  In this study, The first molars of 8 patients, the second molars of 1 patient , and both the first and second molars of 5 patients were intruded by the MI appliance. www.indiandentalacademy.com
  16. 16. >In this study, the intrusive force for molars ranged between 110gm and 180 gm, depending on whether only one or two molars were to be intruded. >The results showed that the mean maxillary and mandibular molar intrusion was 1.86 and 1.04 mm. However, when both the first and second molars were intruded, the average molar intrusion was reduced by nearly half. It was considered that 180 g of force might be insufficient for intrusion of two molars. >Patient compliance problems due to dislodgement were not observed, but MI may pose dislodgement problems in the patients with deficient crown length and buccal undercuts. www.indiandentalacademy.com
  17. 17. It is difficult to use the upper springs of the MI with expansion screws. However, they can be used if precise readjustments are made during expansion.  Mandibular incisors were stable after the MI was used, but the maxillary incisors were extruded an average of 0.54 mm with a labial tipping of 1.46°. This was attributed to the anterior force vector of the lower springs.  Controlling the vertical dimension requires more effort, it is hard to achieve this goal with high-pull headgear, extraction therapy or combination of both because of compensatory eruption of posterior teeth. www.indiandentalacademy.com
  18. 18.  Radiograph showed minimal root resorption in the molars(3 patients). The resorption rate was minimal.  The long-term effects of the treatment have not been established. www.indiandentalacademy.com
  19. 19. CONCLUSIONS  MI is effective in intruding the molars and in reducing the anterior openbite.  MI is also effective in selective molar intrusion.  The intrusive effect of the MI springs almost doubled in the absence of second molars.  MI use may be difficult in the patients presenting deficient crown length. www.indiandentalacademy.com
  20. 20. thank y u For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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