Korean J Orthod.  2015 Jan;45(1):38-46. 10.4041/kjod.2015.45.1.38.

Early treatment of anterior open bite: Comparison of the vertical and horizontal morphological changes induced by magnetic bite-blocks and adjusted rapid molar intruders

• Albogha MH
• Takahashi
• Sawan MN

• KMID: 2074821
• DOI: http://doi.org/10.4041/kjod.2015.45.1.38

Abstract

OBJECTIVE
This prospective clinical study aims to determine the differences between two treatment modalities for anterior open bite in growing patients. The treatment modalities involved the use of magnetic bite-blocks (MBBs) or rapid molar intruders (RMIs) applied with posterior bite-blocks.
METHODS
Fifteen consecutive patients with a mean age of 11.2 (standard deviation [SD] = 1.6) years and a mean open bite of -3.9 mm were treated with MBBs. Another 15 consecutive patients with a mean age of 10.9 (SD = 1.8) years and a mean open bite of -3.8 mm were treated with RMIs applied on bite-blocks. Cephalometric radiographs were obtained before (T1) and immediately after appliance removal (T2). The treatments lasted four months, during which the appliances were cemented to the teeth. The morphological changes were measured in each group and compared using logistic regression analysis.
RESULTS
The MBB group exhibited significantly greater decreases in SNA angle, ANB angle, overjet, and maxillary incisor angle (p < 0.05). The MBBs induced greater effects on the maxilla and maxillary dentition. The MBBs restrained maxillary forward growth and retracted the maxillary incisors more effectively than did the RMIs. Consequently, changes in the intermaxillary relationships and overjets were more distinct in the MBB group.
CONCLUSIONS
The anteroposterior differences between the appliances suggest that MBBs should be preferred for the treatment of patients with Class II open bites and maxillary incisor protrusions.

Keyword

Early treatment; Anterior open bite; Rapid molar intruder; Magnets

MeSH Terms

Dentition
Humans
Incisor
Logistic Models
Maxilla
Molar*
Open Bite*
Overbite
Prospective Studies
Tooth

Figure

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  Figure 1 Magnetic bite-blocks in the mouth. Buccal wings were added to the lower biting-blocks to prevent the development of posterior crossbite.

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  Figure 2 Rapid Molar Intruder (RMI) in the mouth. Instead of the bands on the first molars, the RMI was applied to tubes attached to the posterior bite blocks.

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  Figure 3 Cephalometric parameters measured in the study: SNA angle, angle between anterior cranial base (SN) and point A; SNB angle, angle between anterior cranial base (SN) and point B; ANB, angle between lines NA and NB; SN-MP (mandibular plane angle), angle between SN and mandibular plane (GoMe); FMA (mandibular plane angle), angle between GoMe and Frankfurt planes; PP-MP (basal plane angle), angle between palatal plane (ANS-PNS) and GoMe plane; PP-SN (palatal plane angle), angle between SN and ANS-PNS planes; Björk sum, sum of N-S-Ar (Ar: articulare), S-Ar-Go and Ar-Go-Me; N-Go-Me, lower gonial angle; N-Go-Ar, upper gonial angle; Facial axis, angle between the Ba-N and the PT-Gn planes (Ba: basion, PT: pterygoid); N-Me, distance between N and Me; S-Go, distance between S and Go; S-Go/N-Me, ratio of posterior facial height to anterior facial height; N-ANS, distance from N to ANS perpendicular to horizontal plane (HP is drawn 7 degrees from the SN plane); ANS-Me, distance from ANS to Me perpendicular to HP; PNS-N, distance from PNS to N perpendicular to HP; U1∧SN, maxillary incisor angle to SN plane; U1∧PP, maxillary incisor angle to palatal plane; L1∧MP, mandibular incisor angle to mandibular plane; U1∧L1, angle between the mandibular and maxillary incisors; U1-PP, perpendicular distance from maxillary 1 to the palatal plane; L1-MP, perpendicular distance from mandibular 1 to the mandibular plane; U6-PP, perpendicular distance from maxillary 6 to the palatal plane; L6-MP, perpendicular distance from mandibular 6 to the mandibular plane; Overbite, distance between maxillary 1 and mandibular 1, perpendicular to the static occlusal plane; Overjet, distance between maxillary 1 and mandibuler 1 (parallel to the static occlusal plane); OP-SN, occlusal plane angle with SN.

• 

  Figure 4 Increases in overbite were noticed in all patients, although complete open-bite closure was not achieved in all cases. A, A 13 years old patient (M.A.) and a 12.7 years old patient (N.A.) were treated with magnetic bite-blocks. B, A 13.4 years old patient (A.H.)and a 12 years old patient (Y.N.) were treated with rapid molar intruder attached to bite-blocks.

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  Figure 5 Proposed effects of magnetic bite-blocks. In addition to the upward intrusive force on the maxillary posterior segments, the lip seal adds another force component on the anterior segment. The result is the restraint of downward and forward maxillary growth and anterior rotation of the mandible.

Reference

1. Cangialosi TJ. Skeletal morphologic features of anterior open bite. Am J Orthod. 1984; 85:28–36.

2. Sankey WL, Buschang PH, English J, Owen AH 3rd. Early treatment of vertical skeletal dysplasia: the hyperdivergent phenotype. Am J Orthod Dentofacial Orthop. 2000; 118:317–327.

3. English JD. Early treatment of skeletal open bite malocclusions. Am J Orthod Dentofacial Orthop. 2002; 121:563–565.

4. Iscan HN, Sarisoy L. Comparison of the effects of passive posterior bite-blocks with different construction bites on the craniofacial and dentoalveolar structures. Am J Orthod Dentofacial Orthop. 1997; 112:171–178.

5. Işcan HN, Akkaya S, Koralp E. The effects of the spring-loaded posterior bite-block on the maxillo-facial morphology. Eur J Orthod. 1992; 14:54–60.

6. Gurton AU, Akin E, Karacay S. Initial intrusion of the molars in the treatment of anterior open bite malocclusions in growing patients. Angle Orthod. 2004; 74:454–464.

7. Dellinger EL, Dellinger EL. Active vertical corrector treatment--long-term follow-up of anterior open bite treated by the intrusion of posterior teeth. Am J Orthod Dentofacial Orthop. 1996; 110:145–154.

8. Dellinger EL. A clinical assessment of the Active Vertical Corrector--a nonsurgical alternative for skeletal open bite treatment. Am J Orthod. 1986; 89:428–436.

9. Woods MG, Nanda RS. Intrusion of posterior teeth with magnets. An experiment in growing baboons. Angle Orthod. 1988; 58:136–150.

10. Melsen B, McNamara JA Jr, Hoenie DC. The effect of bite-blocks with and without repelling magnets studied histomorphometrically in the rhesus monkey (Macaca mulatta). Am J Orthod Dentofacial Orthop. 1995; 108:500–509.

11. Meral O, Yüksel S. Skeletal and dental effects during observation and treatment with a magnetic device. Angle Orthod. 2003; 73:716–722.

12. Kuster R, Ingervall B. The effect of treatment of skeletal open bite with two types of bite-blocks. Eur J Orthod. 1992; 14:489–499.

13. Barbre RE, Sinclair PM. A cephalometric evaluation of anterior openbite correction with the magnetic active vertical corrector. Angle Orthod. 1991; 61:93–102.

14. Kiliaridis S, Egermark I, Thilander B. Anterior open bite treatment with magnets. Eur J Orthod. 1990; 12:447–457.

15. Kalra V, Burstone CJ, Nanda R. Effects of a fixed magnetic appliance on the dentofacial complex. Am J Orthod Dentofacial Orthop. 1989; 95:467–478.

16. Carano A, Machata W, Siciliani G. Noncompliant treatment of skeletal open bite. Am J Orthod Dentofacial Orthop. 2005; 128:781–786.

17. Cinsar A, Alagha AR, Akyalçin S. Skeletal open bite correction with rapid molar intruder appliance in growing individuals. Angle Orthod. 2007; 77:632–639.

18. Dahlberg G. Statistical methods for medical and biological students. London: George Alien and Unwin Ltd;1940.

19. McNamara JA Jr. An orthopedic approach to the treatment of Class III malocclusion in young patients. J Clin Orthod. 1987; 21:598–608.

20. Buschang PH, Jacob H, Carrillo R. The morphological characteristics, growth, and etiology of the hyperdivergent phenotype. Semin Orthod. 2013; 19:212–226.

21. Bourauel C, Köklü SO, Vardimon AD. Integrated magnetic and elastic force systems. Am J Orthod Dentofacial Orthop. 2002; 122:155–163.