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Case Report
Use of a modified anterior inclined plane in the treatment on the dentoskeletal Class II division 2 patient Abstract Class II malocclusions are seen due to the underdevelopment of the mandible in most of the cases. To compensate for the mandible retrusive position, there is flaring of the lower anterior teeth or retroclination of the central incisors as a compensatory mechanism seen in Class II division 2 type of malocclusion. This case report evaluates the skeletal and dental changes when a 12-year-old female patient with Class II div 2 malocclusion was treated with a modified anterior inclined plane. The postreatment data suggested that there were no significant changes in the vertical skeletal parameters. The upper central incisors were significantly realigned by proclination along with retroclination of the lateral incisors. There was significant increase in the mandibular length. The results revealed that the modified anterior inclined plane showed good results in the treatment of a case of Class II div 2 malocclusion.
Key words Functional therapy, inclined plane, skeletal Class II div 2 malocclusion
Introduction Functional appliances are powerful appliances capable of impressive changes in the position of the teeth. These appliances direct the pattern and direction of growth of the jaws by alteration of the forces produced by the whole neuromuscular component.[1-3] They are generally used for Class II div 1 malocclusions, although they can be used for the correction of Class II div 2 and Class III malocclusions on occasion. They are either removable from the mouth or fixed to the teeth, and work by stimulating the muscles of mastication
Rao SA, Thomas AM1, Chopra S2
PG Resident, 1Principal and 1,2Professor, Department of Pediatric Dentistry, Christian Dental College, Brown Road, Ludhiana, Punjab, India. Correspondence: Dr. Sreedhar Rao A, Department of Pediatric Dentistry, Christian Dental College, Brown Road, Ludhiana - 141 008, Punjab, India. E-mail:
[email protected]
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Website: www.jisppd.com DOI: 10.4103/0970-4388.73782 PMID: *****************************
and soft tissues of the face. Majority of the appliances are used in the correction of Class II malocclusions by stimulating the growth of the mandible. Changes are induced by holding the mandible forward and the ensuing reaction of the stretched muscles and soft tissues, transmitted to the periosteum, bones and the teeth.[4] A restraining effect on the growth of the maxilla and the maxillary dentoalveolar complex is also seen along with the stimulation of mandibular growth and mandibular alveolar adaptation. Favorable changes in temporomandibular joint also occur.[5-7] The most common appliance used is the twin block appliance, which eliminates the major disadvantage of other functional appliances, such as activator, bionator, and Frankel’s vestibular appliances, which are fabricated in one piece to fit the teeth in both the jaws due to which the patient cannot eat or speak and hence finds it uncomfortable for full-time wear.
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Rao, et al.: Modified Anterior inclined plane: treatment class II div 2
The twin block though the most preferred and used appliance still has its own disadvantages, in that it still is somewhat bulky, and some amount of discomfort exists with speech and mastication. The other problem is that it has a long treatment time with the appliance being changed and altered in the supportive and retentive phase.[8-10]
Table 1: Comparison of pre treatment and post treatment dentoskeletal changes with inclined plane treatment Measurements
Pretreatment
Post-treatment
SNA
82
82.5
SNB
76
78.9
ANB
5
4
76.5
79
SN-Pog Y-axis
To do away with disadvantages of the twin block and other functional appliances, the anterior inclined plane was developed.[11] The inclined plane is a removable intermaxillary appliance that forces the mandible to move in a forward position during the mandibular functional activity, particularly during the swallowing period. Protractor muscle involvement results in the intermittent activation of the retractor muscles that leads to favorable bone remodeling. In comparison with the traditional functional appliances, this appliance does not restrict the three-dimensional mandibular movement nor does it interfere with the regular physiologic activity of the oral cavity, which has a great impact on the patient cooperation, and it requires less effort by the patient to follow oral hygiene instructions. The anterior inclined appliance has shown good results in the treatment of Class II div 1 patients. There still exists a concern in the treatment of Class II div 2 malocclusion cases. The twin block has a modification for the same but the appliance still has the same disadvantages of the regular twin block. The other option includes converting the Class II div 2 to a Class II div 1 case and to continue the treatment. This whole procedure becomes time-consuming and cumbersome. In this study, we used an anterior inclined plane within which was incorporated a double cantilever spring to treat a case of Class II div 2 malocclusion.
Case Report A 12-year-old female presented with retroclined maxillary central incisors and proclined maxillary lateral in the Department of Pediatric and Preventive Dentistry. The patient was in the mixed dentition stage with a skeletal Class II–jaw base relationship. She had bilaterally retained upper and lower first and second deciduous molars. The patient also had with anterior deep bite, which is a typical presentation of a Class II div 2 malocclusion [Figure 1]. Radiographs revealed the presence of all permanent teeth except upper right second premolar, which was congenitally absent. 238
66
65.5
23.5
23
Ar-A
89
89.5
Ar-B
90.5
93
Ar-Pog
97
100.5
1-SN
96
99
MP–SN
SNA: Sella- nasion- pt A; SNB: Sella- nasion- pt B; ANB: pt A- nasion- Pt B; SN-Pog: sella-nasion-pogonion; MP–SN: mandibular plane-sella-nasion; Ar-A: articulare-pt A; Ar-B: articulare-pt B; Ar-Pog: articulare-pogonion; 1-SN: incisor edge of maxillary central incisorsella-nasion
An anterior inclined plane was incorporated in the upper arch with a double cantilever spring to procline the central incisors [Figures 2 and 3]. The inclined plane is a removable appliance wherein during mouth closure; the mandible moves in the forward position. The appliance was constructed in such a manner that as the central incisors proclined, the mandible glided forward utilizing the incline created palatal to the lateral incisors. So the appliance did not need to be modified with the proclination of the central incisors. Once the central incisors had sufficiently proclined, the labial bow was also activated to retrocline the lateral incisors with adequate clearance of acrylic on the palatal side of these teeth. The patient visited once every week for the cantilever spring and the labial bow activation thereafter.
Results Comparisons of the pretreatment and posttreatment data of the pretreatment and posttreatment are shown in Table 1. The comparison of the cephalometric measurements revealed that the appliance had not much skeletal effect on the maxilla. There was no change in the sella-nasion-pt A (SNA) angle. The skeletal vertical parameters were evaluated and no significant change was found in sella-nasion-mandibular plane (SN–MP) and Y axis. When the measurements of the mandible were evaluated, significant changes were found. The Pt A-nasion-Pt B (ANB) angle demonstrated a decrease of 1° when the 2 cephalograms were compared. Changes in Articulare-pt B (Ar-B), articulare-pogonion (Ar-Pog), and sella-nasion-pt B (SNB) were significant. The dental changes caused by the inclined plane were obvious. The
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Rao, et al.: Modified Anterior inclined plane: treatment class II div 2
Figure 1: Pretreatment frontal view Figure 2: Appliance in the mouth
Figure 3: Frontal view of appliance in mouth
Figure 5: Occlusion right side—posttreatment
upper central incisors were significantly realigned by proclination along with retroclination of the lateral incisors [Figures 4,5 and 6].
Discussion A review of the literature shows that there have been no studies done so far in the use of the reverse inclined
Figure 4: Posttreatment frontal view
Figure 6: Occlusion left side—posttreatment
plane in the treatment of Class II div 2 malocclusion. There is only one study where the reverse inclined plane has been used in the treatment of 25 cases of Class II div 1 cases with promising results. Anterior inclined plane application in a previous study and in our case overcame many disadvantages of the conventional functional appliances. In this study, the results of
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Rao, et al.: Modified Anterior inclined plane: treatment class II div 2
treatment in Class II div 2 with this type of appliance are evaluated. The inclined plane is a removable intramaxillary appliance that forces the mandible to move in a forward position during the mandibular functional activity, particularly during the swallowing period.[11] In this appliance, we also incorporated a double cantilever spring for proclination of the central incisors and also a labial bow was incorporated to retrocline the lateral incisors into the arch. In comparison with the traditional functional appliances, this appliance does not restrict the three-dimensional mandibular movement nor it interferes with the regular physiologic activity of the oral cavity, which has a great impact on the patient cooperation, and it requires less effort by the patient to follow oral hygiene instructions. This method is more effective in early stages of Class II deep bite malocclusion treatment, particularly to redirect the mandibular growth anteriorly and vertically by eliminating the lack of occlusion that acts as a physical barrier against the normal growth of the mandible.[1,12] This appliance prevents the further extrusion of the upper and lower anterior teeth because of the loss of anterior incisal contact. It provides a greater extrusion of the lower posterior teeth and this helps to correct the Class II relationship and opens the bite simultaneously in the early mixed dentition period. The results showed that Class II correction was achieved mostly through dentoalveolar and skeletal changes of the mandible and revealed that the appliance had no effect on the nasomaxillary growth component. Inclined plane favorably improved the profile and the double cantilever spring proclined the upper central
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incisors. As the position of the incisors improved so did the contour of the upper lip resulting in better esthetics and improved profile.
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Source of Support: Nil, Conflict of Interest: Nil
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