A novel method for the treatment of Class II malocclusion

Growth modification is a feasible approach for the treatment of skeletal Class II malocclusion. A positive association was found between the lateral functional shift of the mandible due to occlusal prematurities and skeletal changes. This finding is reminiscent of an equivalent anteroposterior skeletal effect of the anterior functional shift of the mandible. Inclined planes can be considered as a form of premature contact. In this case, bonded occlusal maxillary and mandibular bite raisers were used to create occlusal prematurities artificially. These bonded inclined bite raisers are used in conjunction with full-time light short Class II elastics. The results showed an improvement in profile convexity and achievement of Class I canines and molars. The bonded inclined bite raisers combined with light and short intermaxillary elastics can correct Class II malocclusion and improve the soft tissue profile.

Highlights

  • Class II malocclusion treatment with occlusal prematurities to enhance growth modification.

  • Technique is based on bite raisers placed on the occlusal surface of molars and/or premolars.

  • Light Class II elastics are used to guide the intended mandibular closure direction.

  • Results show profile improvements and Class I canine and molar relationship.

Skeletal Class II malocclusion occurs in 15%-30% of different populations. In 1981, McNamara showed that up to 85% of patients with Class II malocclusion have some component of mandibular deficiency underlying the skeletal Class II discrepancy. The treatment of patients with skeletal Class II malocclusion ranges from dental compensation, including camouflage by extractions, to surgical management. In growing patients, growth modification is a feasible and more conservative approach, which is more appealing than camouflage, because ideally, the skeletal discrepancy should be addressed for optimal treatment results. Functional appliances are used to treat skeletal Class II problems due to mandibular deficiency in growing patients. Removable functional appliance therapy depends totally on the patient’s cooperation, which is complicated by appliance bulkiness. Fixed functional appliances suffer many other drawbacks including difficult fabrication, easy breakage, and tissue irritation.

Functional shift of the mandible is a condition that occurs in cases with occlusal prematurities. The patient shifts the mandible to avoid traumatic occlusal interferences and attain a comfortable bite. A positive association between lateral functional shift of the mandible and skeletal changes was supported by many studies. This finding is equivalent to the possible anteroposterior skeletal effect of the anterior functional shift of the mandible in pseudo–Class III cases.

Artificially-induced occlusal interferences have been previously used for many experimental purposes. They were created to test the impact of premature contacts on the muscular activity, pulpal reactions, and development of temporomandibular disorder and periodontal disease. ,

Inclined planes can be considered as a form of premature contact. They were introduced as early as 1899 and were termed buccal planes. Previously, Dr. Edward Angle used a plane and spur for the retention of cases in which the bite was jumped using the Kingsley biteplate. Historical attempts to use inclined bite planes in correcting malocclusions and stimulation of forward growth of the mandible have been recorded. ,

This case report presents a novel approach in the treatment of skeletal Class II malocclusion in growing patients. It comprises the use of bonded occlusal maxillary and mandibular bite raisers to create occlusal prematurities artificially. These bite raisers are made with a complementary inclination that guides the mandible forward as the patient bites—a mechanism similar to that of a Twin-block appliance. The result is a full-time intentional functional forward mandibular slide. These bonded inclined bite raisers are used in conjunction with full-time light short Class II elastics (ie, bonded inclined bite raisers elastics [BIBRE]).

Bibre construction: indirect method

A 2 mm symmetric advancement wax bite was made for the patient. Maxillary and mandibular impressions were taken, and the poured models were mounted on an articulator using the wax bite. A separating medium was applied to the models and allowed to dry. Complimentary inclined bite raisers were constructed on the occlusal surfaces of 2 occluding molars or premolars on the patient’s model using light cure glass ionomer, triad gel, compomer, or colored filled composite. The selection of sites for the bite raisers was made according to the patient’s overbite. In the case of a deepbite, the raisers were made on the premolars to facilitate molar extrusion, whereas, in the case of an open bite, they were made on the molars to effect molar intrusion and subsequent closure of the open bite.

The mandibular raisers were beveled 45° distally, whereas the maxillary raisers were beveled 45° mesially ( Fig 1 ). The articulator was opened and closed to ensure proper contact between the bite raisers. The upper member of the articulator was also moved side-to-side to detect and remove any interference between the bite raisers. This approach would allow for smooth lateral excursions and less liability of breakage. Transfer trays were then made using vacuum-formed 1.5 mm soft Essix sheets (Essex C Sheets, Dentsply, Sirona, Long Island City, NY). The bite raisers were then removed from the models, cleaned, and bonded to the occlusal surfaces of the patient’s teeth using the transfer trays, phosphoric acid etch, and a thin layer of flowable composite. The transfer trays were saved for possible rebonding if the raisers accidentally break.

Fig 1
The maxillary and mandibular raisers beveled 45° mesially and distally, respectively.

The patient was instructed to wear short and light intermaxillary Class II elastics from the maxillary canine to the mandibular first or second premolar full-time to ensure a 2 mm forward mandible slide. In addition, the patient was instructed to avoid hard food to prevent the breakage of the bite raisers. The patient’s bite was checked every 6 weeks, both in centric relation and maximum intercuspation. Activation of the induced functional slide was done only when centric relation coincides with maximum intercuspation, and when further correction was required. This was done by adding 1-2 mm of bonding material on the distal incline of the mandibular bite raisers. After finishing the anteroposterior correction, the maxillary bite raisers were removed, and the mandibular bite raisers were left to stabilize the occlusion for an additional 3 months.

Case 1

Diagnosis and etiology

A 13-year-old girl reported to the clinic with the chief complaint of an unpleasant profile. Clinical examination showed a convex profile with accentuated mentolabial sulcus. She showed a nonconsonant smile. The patient was in the permanent dentition stage. She had Class II molars and canines, with 8 mm of overjet and complete overbite. She had mild maxillary and mandibular arch crowding ( Figs 2 and 3 ). The panoramic radiograph showed normal bone and tooth forms with developing third molars. Cephalometric analysis revealed a Class II skeletal base with protrusive maxilla, retruded mandible, and retrusive upper and lower lips ( Fig 4 ).

Fig 2
Pretreatment facial and intraoral photographs.

Fig 3
Pretreatment dental casts.

Fig 4
Pretreatment lateral cephalogram and panoramic radiograph.

Treatment objectives

The treatment objectives were to obtain a straight profile, correct the overbite, improve lip position, obtain Class I skeletal relationship, correct the canine and molar relation, alleviate crowding, and achieve proper alignment and inclination of teeth.

Treatment alternatives

Based on the treatment objectives, the following alternatives were presented to the patient and her parents:

  • 1.

    Maxillary first premolars’ extraction to correct Class II relations and obtain proper overjet. This treatment approach would correct the dental relation, but it could worsen the profile.

  • 2.

    Distalization of the maxillary dentition using extraoral or intraoral appliances. This treatment approach would correct the occlusal discrepancy, but it would not correct the soft tissue profile and underlying skeletal discrepancy.

  • 3.

    The use of the BIBRE in conjunction with a fixed appliance to improve the profile and occlusal relations.

The patient and her parents refused extraction and the unsatisfactory treatment results of distalization and chose the third option to correct both profile and occlusal discrepancies.

Treatment progress

After bidimensional straight wire Roth brackets (Mini Diamond; Ormco, Brea, Calif) were bonded in both arches, 0.014-in nickel-titanium (NiTi) archwires were placed for alignment. A sequence of alignment NiTi archwires was inserted until 0.016-in × 0.022-in was reached. A BIBRE made of compomer (Twinky Star; Voco, Cuxhaven, Germany) was placed on maxillary and mandibular first permanent premolars. Light elastics (3/16-in) delivering 75 g of force intermaxillary elastics were applied between maxillary canine and first premolar to mandibular first premolar and first molar. The patient was instructed to change the elastics every 24 hours ( Fig 5 ).

Jan 9, 2021 | Posted by in Orthodontics | Comments Off on A novel method for the treatment of Class II malocclusion
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