Anterior Open Bite Correction Using Bite Block - Case Report [PDF]

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Anterior open bite correction using bite block: a case report Article  in  International journal of orthodontics (Milwaukee, Wis.) · August 2012 Source: PubMed



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Anterior Open Bite Correction Using Bite Block: A Case Report By Roger Teixeira Gazinelli de Barros, Paulo Pelucio Câmara, Antônio Carlos Aloise, Danilo Furquim Siqueira, Luiz Renato Paranhos, Fernando César Torres Abstract: Several etiological factors that result in dental and/or skeletal alterations make the open bite a type of malocclusion with several treatment alternatives. Corrective fixed orthodontics in conjunction with mechanical or functional orthopedics is a routine approach in correcting this problem. However, orthosurgical treatment must never be discarded for cases with skeletal involvement. This article describes a clinical case which, despite involving skeletal aspects, was treated satisfactorily using a passive bite-block appliance in conjunction with corrective fixed orthodontics. Key words: open bite, orthodontics ntroduction The treatment of malocclusions characterized by anterior open bite in nongrowing patients represents one of the most difficult challenges in orthodontic practice. The causes of these alterations can range from vertical skeletal growth discrepancies, habit disorders, or an association of both factors – characterizing a multifactorial etiology.1,2,3,4,5 Bite blocks can be successfully used as a nonsurgical alternative for treatment of anterior open bite, when the aim is to obtain not only extrusion of anterior teeth, but a possible intrusion of posterior teeth, rotating mandible in a counter clockwise way and decreasing the anterior facial height. These appliances were initially conceived as acrylic tracks that artificially increased vertical dimension, or spring-loaded appliances that exercised the mandibular elevator muscles. The objective of this therapy is to readapt the muscular system, increasing muscle power, which in turn would lead to intrusion or contention in the eruption of posterior teeth.9,10,11 Some clinicians have incorporated magnets into these appliances, giving additional power to muscle strength.8,9,10,11,12,13,14 This article presents a clinical case of a nongrowing female patient, with anterior and posterior open bite (both dental and skeletal), treated with acrylic bite blocks. CASE REPORT DIAGNOSIS AND ETIOLOGY A female patient, 16 years and 10 months of age, came for treatment at the Graduation Course in Orthodontics of Brazilian Association of Orthodontics (Sete Lagoas, MG, Brazil). A facial analysis detected an increased facial lower third, as well as a mandibular retrusion (Figure 1), which was later confirmed through cephalometric exams. IJO  VOL. 23  NO. 2  SUMMER 2012



Figure 1 - Extrabuccal photographs



Table 1: Standard and initial cephalometric measurements Measurement



Standard



Initial



SNA



82°



84°



SNB



80°



78°



ANB



2°



6°



FMA



25°



33°



FMIA



68°



58°



IMPA



87°



90°



AFH



62mm



71mm



1.NA



22°



32°



1-NA



4mm



7mm



1.NB



25°



30°



1-NB



4mm



8mm



11



After anamnesis, clinical exams, radiographic and model analysis, the following intrabuccal alterations were identified:  dental and skeletal anterior open bite that reached into the area of the canines, with a 6-mm magnitude, and extended back to the first molars, though with less intensity (Figure 2);  Class I molar relationship;  presence of diastemas in the maxillary and mandibular arches. The etiology of the malocclusion diagnosed in the patient was a combination of vertical growth associated with habit disorders, as suggested by several authors,4,14 which resulted in the dental and skeletal alterations shown in Figure 3 and Table 1.



Figure 2 - Intrabuccal photographs



Figure 3 - Dentoskeletal alterations



Figure 4 - Bite Block



TREATMENT OBJECTIVES The objective of the proposed orthodontic and orthopedic treatment was to: 1. Correct the open bite; 2. Eliminate the diastemas; 3. Obtain a functional and stable occlusion. TREATMENT ALTERNATIVES The proposed therapies for the correction of this malocclusion are varied. Perhaps the best known is vertical dentoskeletal control, using extraoral headgear and palatal bars or, more recently, utilizing miniimplants or miniplates, in conjunction with extrusion of anterior teeth using intermaxillary elastics.15 Orthognatic surgery should never be discarded as an option in cases with skeletal involvement. The treatment proposed for this patient was the use of a Bite Block built in a centric relation, with an acrylic track to promote an increase of 4mm in the molar regions, and 3 mm of palate relief (Figure 4). 6,13,16



Table 2: Standard, Initial, final and difference of cephalometric measurements



12



Measurement



Standard



Initial



Final



Difference



SNA



82°



84°



84°



0°



SNB



80°



78°



81°



+3°



ANB



2°



6°



3°



-3°



FMA



25°



33°



29°



-4°



FMIA



68°



58°



62°



+4°



IMPA



87°



90°



88°



-2°



AFH



62mm



71mm



68mm



-3mm



1.NA



22°



32°



23°



-9°



1-NA



4mm



7mm



3mm



-4mm



1.NB



25°



30°



23°



-7°



1-NB



4mm



8mm



6mm



-2mm



TREATMENT EVOLUTION The Bite Block was installed (Figure 5) and the track was adjusted to obtain maximum bilateral contact with lower teeth, pressing softly the patient`s chin, bilaterally, to put the mandible in centric relation. Internally, the acrylic was abraded in the premolar region in order to keep the intrusion restricted to the molars, and the premolars were intruded as necessary. The patient was instructed to wear the appliance approximately 24 hours a day, including during meals, if possible, which was promptly followed by the patient. Bi-weekly check-ups were scheduled, in order to keep the appliance with the IJO  VOL. 23  NO. 2  SUMMER 2012



Figure 9 - Superimposition of results Figure 5 - Applied Bite Block



Figure 6 - Interarch relationship after four months of Bite Block use



Figure 7 - Alignment and leveling



Figure 8 - Interarch relationship after treatment IJO  VOL. 23  NO. 2  SUMMER 2012



maximum contact between the Bite Block track and lower teeth, as well as to motivate the patient. After four months, the decision was made to place the fixed appliance, as positive overbite had already been achieved in the anterior region (Figure 6). Speech therapy also began during this stage, although the patient had been referred at the beginning of treatment for diagnosis of possible habit disorders. The selected appliance was a pre-adjusted type, MBT Prescription (3M, Unitek®). Alignment and leveling began with 0.014” nickel-titanium wires. Intermaxillary elastics (3/16” – medium force) were used full-time, from the fourth to seventh month of corrective fixed orthodontics in the areas of the upper canines and lower premolars, to improve the intercuspation (Figure 7). The closing of the diastemas was performed with the use of medium-force chain elastics, while intercuspation was achieved using 1/8” heavy-force elastics, with 0.019x0.025” steel wire for the lower dentition and multi-strand steel wire for the upper teeth. The active phase of the treatment lasted 16 months, after which upper and lower removable retainers were used (acrylic resin plates with 0.8mm stainless steel wire, around the teeth, contacting their buccal faces), full-time during 12 months, and then for six more months during sleep. Additionally, a fixed retainer was used, bonded behind lower canines. TREATMENT RESULTS After appliance removal, an adequate relation was observed between upper and lower teeth for all three spatial planes (Figure 8). Laterality functions were performed by the canines, and protrusion was exercised by the four incisors – upper and lower—without interference from the other teeth. It was verified that centric relation was coincident with the maximal intercuspation. Frontal and lateral views of patient’s face showed a slight enhancement of lips sealing and anterior facial height (Figure 9). The correction of this malocclusion was the result of counterclockwise rotation of the mandible, verticalization and extrusion of the lower incisors, intrusion of the molars 13



Figure 10 - Smile, five years after treatment



Figure 11 - Five-year follow-up



and verticalization of the maxillary incisors, as can be seen in the superimposition tracing (Figure 10). Cephalometric alterations are disclosed in Table 2. The measurement FMA was reduced 4 o, due to mandibular rotation, which promoted a more anterior chin placement and a decrease of anterior facial height (AFH), in 3mm. After three years, the removable retainer was removed and replaced by a fixed retainer, spanning from the upper right canine to the left. This retainer was designed so as to allow free access to the interdental region for flossing. The patient was instructed to no longer use the lower retainer, and new photographs were taken five years after conclusion of the case. The five-year follow-up after removal of the appliance showed only a clinically insignificant relapse, meaning the stability achieved was considered satisfactory (Figure 11). DISCUSSION For the treatment of anterior open bite, two factors must be analyzed: treatment objectives and the stability of the specific case. The therapies recommended for the correction of this malocclusion can be orthopedic or orthodontic, with the aim of promoting dental or dentoalveolar compensation. The treatment can also be performed with the aid of orthognatic or orthopedic surgery for skeletal correction. Surgical correction is routinely indicated for nongrowing patients with skeletal alterations. That treatment consists basically of maxillary intrusion, with counterclockwise mandible rotation. The treatment proposed for this patient was 14



orthodontic in association with orthognatic surgery; the patient, however, was not willing to undergo the surgical phase. As a second option, the full-time use of the Bite Block 24 was suggested, although the patient’s age was not ideal for this treatment. The Bite Blocks considered passive are occlusal tracks of varied heights which artificially alter the vertical dimension.14 The thickness of the appliance normally exceeds the 3-4 mm free space in the posterior region, and a 3-mm relief must be provided in the palate area. During treatment, the orthodontist must adjust the Bite Block track, so as to maintain the maximum amount of contact with lower teeth; when necessary, acrylic must be added to this track in order to maintain the increase in vertical dimension. In the case mentioned here, the alterations produced by the Bite Block in the patient were predominantly dental, with moderate skeletal repercussions either vertically or sagitally. Given that facial form is partially determined by muscular activity, this suggests that the increase in power of the masticatory muscles can be beneficial to facial growth in children with excessive vertical height. 6,7,15,17 During the first three months, the alterations were more pronounced than in the fourth to fifth months. As it maintains constant tension on the neuromuscular system of the mandible (especially in the masseter muscle), this appliance was effective in closing the bite within a short period of time; however, muscular activity decreased or remained constant after a certain treatment period.7 Five years after treatment, a slight relapse was observed IJO  VOL. 23  NO. 2  SUMMER 2012



in the right upper lateral incisor, considered clinically insignificant, if compared to the correction that did not involve orthognatic surgery. CONCLUSION Promoting intrusion of posterior teeth and controlling their eruption is not a recent therapy. The artificial decrease of vertical dimension through the use of acrylic blocks appeared as a non-surgical alternative for the treatment of open bite. With time, new features were added to Bite Blocks, making them resilient (elastic activator), springloaded or activated by magnetic force.8,9,10,11,12,14,20 No studies have found any side effects in temporomandibular joint or in the neuromuscular system. However, transitory gingivitis in cemented appliances and transitory unilateral crossbite in the Bite Blocks with magnets18,19 were found. This article showed a successful treatment using the Bite Block for the correction of anterior open bite with moderate skeletal involvement.



14. Darendeliler MA, Darendeliler A, Mandurino M. Clinical application of magnets in orthodontics and biological implications: a review. Eur J Orthod 1997;19:431-42. 15. Insoft MD, Hocevar RA, Gibbs CH. The nonsurgical treatment of a Class II open bite malocclusion. Am J Orthod Dentofacial Orthop 1996;110:598-50. 16. Barbre RE, Sinclair PM. A cephalometric evaluation of anterior openbite correction with the magnetic active vertical corrector. Angle Ortho 1991;61:93-102. 17. Kuster R, Ingervall B. The effect of treatment of skeletal open bite with two types of bite blocks. Eur J Orthod 1992;14:489-99. 18. Darendeliler MA, Yuksel S, Meral O. Open-bite correction with the Magnetic Activator Device IV (MAD IV). J Clinical Orthod 1995;29:569-76. 19. Melsen B, Mac`Namara J, 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;108:500-09. 20. 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;110:145-54.



REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.



Lowe AA. Correlations between orofacial muscle activity and craniofacial morphology in a sample of control and anterior open bite subjects. Am J Orthod 1980;78:89-98. Nanda SK. Patterns of vertical growth in the face. Am J Orthod 1988; 93 :103-16. Nielsen IL. Vertical malocclusions: etiology, development, diagnosis and some aspects of treatment. Angle Orthod 1992;61:247-60. Ueda HM, Myamoto K, Saifuddin IY, Tanne K. Masticatory muscle activity in children and adults with different facial types. Am J Orthod Dentofacial Orthop.2000;118: 63-68. Ingervall B, Bitsanis E. A pilot study of the effect of masticatory muscle training on facial growth in long-face children. Eur J Orthod 1987;9:15-23. Akkaya S, Haydar S, Bilir E. Effects of spring-loaded posterior bite-block appliance on masticatory muscles. Am J Orthod Dentofacial Orthop 2000;118:179-83. Cozza P, Mucedero M, Braccetti T, Franchi L. Early Orthodontic treatment of skeletal open-bite malocclusion: A systematic review. Angle Ortho 2005;75:707-713. Dellinger EL. A clinical assessment of the Active Vertical Corrector: A nonsurgical alternative for skeletal open bite treatment. Am J Orthod Dentofacial Orthop 1986;89:428-36. Woods MG, Nanda RS. Intrusion of posterior teeth with magnets: an experiment in growing baboons. Angle Orthod 1988; 58:13650. Kalra V, Burstone CJ, Nanda R. Effects of a fixed magnetic appliance on the dentofacial complex. Am J Orthod Dentofacial Orthop 1989; 95: 467-78. Kiliaridis S, Inger E, Birgit T. Anterior open bite treatment with magnets. Eur J Orthod 1990;12:447-57. Noar JH, Shell N, Hunt NP. The physical properties and behavior of magnets used in the treatment of anterior open bite. Am J Orthod Dentofacial Orthop 1996;109: 437-44. Noar JH, Shell N, Hunt NP. The performance of bonded magnets used in the treatment of anterior open bite. Am J Orthod Dentofacial Orthop 1996;111:549-56.



IJO  VOL. 23  NO. 2  SUMMER 2012



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Roger Teixeira Gazinelli de Barros*, Paulo Pelucio Câmara*, Antônio Carlos Aloise**, Danilo Furquim Siqueira***, Luiz Renato Paranhos****, Fernando César Torres**** * Master’s Degree in Orthodontics, Methodist University of São Paulo, Brazil. ** Professor, São Paulo University – UNIP *** Professor, Postgraduate Program in Orthodontics, University of the City of São Paulo - UNICID **** Professor, Graduate and Postgraduate Program in Orthodontics, Methodist University of São Paulo. Corresponding author: Dr. Fernando C. Torres R. Nhu-Guaçu, 209, ap. 82 Campo Belo, São Paulo – SP Brazil CEP 046245-001 [email protected] phone: 00 55 11 4366 5826



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