The authors describe a minimally invasive procedure for occlusal rehabilitation in a young patient presenting with mild mandibular prognathism and loss of occlusal vertical dimension caused by dental erosion from chronic gastroesophageal reflux.
The structural loss of dental enamel may result from erosion, abrasion, attrition or abfraction, events that are referred to in the literature as non-carious lesions.1–6 Dental erosion is the result of local, chronic, painless loss of tooth substance due to acid exposure.7–15
The stability of dental enamel is directly dependent on pH and saliva composition: a decrease in the pH of saliva affects tissue integrity.16,19–21 Because the pH of gastric acid is much lower than 5.5 (critical value for the dissolution of dental enamel), the risk of dental erosion is four times greater in patients with weekly regurgitation and may be more than eight times greater in patients with chronic vomiting.22–23 Chronic regurgitation is thus characterized by the appearance of different degrees of erosion on the palatal surfaces of maxillary teeth and the occluso lingual surfaces of mandibular teeth.24
In cases of dental erosion caused by intrinsic factors, clinical signs become evident only one to two years after frequent contact (several times per week) between the acids and dental structure.24 However, it is important to emphasize that dental erosion is not likely to occur only as a result of contact with gastric acid. Associated mechanical factors, such as brushing, tooth attrition and food mastication, also play an important role.24–25 In addition, patients with bulimic disorders may present worn or fractured incisal edges, open bite and loss of occlusal vertical dimension, because of the occlusal wear of posterior teeth. Gland anomalies, xerostomia, cheilitis and irritation of the oral mucosa are also frequently seen in these patients.26–29
The current study describes the diagnosis and treatment of a patient with mild mandibular prognathism and severe erosion associated with gastro-esophageal reflux.
DESCRIPTION OF THE TECHNIQUE
A 24-year-old male patient sought orthodontic treatment, reporting difficulty in bringing his teeth together. The initial physical examination revealed a dental and skeletal Class III relationship and anterior open bite from first molar to first molar. Mandibular asymmetry was also observed, with a 4-mm midline deviation to the left. The patient presented severe generalized erosion on the incisal surfaces of all teeth, on the palatal surface of maxillary teeth and on the buccal surfaces of mandibular teeth (canines and premolars), resulting in loss of occlusal vertical dimension (Figure 1). Based on the suspicion that dental erosion was being caused by a systemic problem, the patient was referred to a gastroenterologist, and a diagnosis of gastro-esophageal reflux was established. Once the treatment for gastro-esophageal reflux was completed, oral rehabilitation was initiated. In the first 24 months post-systemic treatment, the patient underwent frequent medical follow-up.
Placement of the fixed orthodontic apparatus required reconstruction of the mandibular and maxillary molars in order to restore occlusal vertical dimension and provide a surface to which orthodontic brackets and bands could be bonded and banded. This initial restorative treatment primarily consisted of building occlusal surfaces in resin composite without cavity preparation, along with use of an adhesive technique for enamel and dentin.
The first treatment option presented to the patient for the correction of prognathism and mandibular asymmetry was orthodontic treatment, combined with orthognathic surgery of the mandible; this option was refused by the patient, because the patient did not want a dramatic change in his facial profile as a result of surgery. Non-surgical orthodontic treatment was then planned to compensate for the skeletal problem. Stripping the lower teeth was used to level and align the mandibular and maxillary arches. Then, verticalization of the mandibular teeth was carried out and the maxillary teeth were slightly projected forward. The mandibular midline deviation was corrected using Class III elastics on the left side and Class II elastics on the right side. Upon completion of the orthodontic treatment, the patient presented a Class I molar and canine relationship and was then able to initiate functional and esthetic rehabilitation.
List of Materials Used
Brackets (Sybron International, Milwaukee, WI, USA)
Transbond XT, UNITEK (3M ESPE Dental Products, St Paul, MN, USA)
Scotchbond Multipurpose (3M ESPE Dental Products, St Paul, MN, USA)
Filtek Z250, A2 and Filtek P60 B2 (3M ESPE Dental Products, St Paul, MN, USA)
Sof-Lex Pop-On polishing discs (3M ESPE, St Paul, MN, USA)
Silicone points (Cosmedent, Chicago, IL, USA)
Restorative treatment was conducted with the use of resin composites, although longevity of the direct restorations is known to be potentially affected when applied in extreme and over-extended situations. The decision was made based on the following factors: preservation of tooth structure and the patient's age and follow-up time to ensure complete recovery from the systemic condition. Indirect restorations associated with greater longevity would not ensure an adequate longitudinal behavior in this case, as long as the underlying cause of erosion was not resolved, because peripheral dental structures would keep on being exposed to wear.
After local anesthesia and complete isolation of the operating field, the existing restorations were removed and their cavities used as additional retention sources for the new restorative material. Adjacent dental structures to which the adhesive material was later applied were roughened with low-rotation diamond-coated burs to make them reactive to the adhesive system. The restorative phase of the treatment followed the basic steps of adhesive dentistry: 37% phosphoric acid etching of enamel and dentin for 15 seconds, followed by abundant rinsing and drying. Then, a two-component adhesive system (Scotchbond Multipurpose, 3M ESPE Dental Products, St Paul, MN, USA) was applied according to the manufacturer's instructions: 1) application of the primer layer, 2) drying, 3) application of the adhesive layer and 4) light curing for 20 seconds. Subsequently, resin composite (Filtek Z250, A2 and Filtek P60 B2, 3M ESPE Dental Products) was applied in ≤2-mm-thick layers using the incremental technique. Each layer was light cured for 40 seconds. This procedure was repeated until the tooth was fully restored, always with rubber dam isolation, which was a key factor for the achievement of adequate adhesion results (Figure 2).
In order to ensure functional stability, treatment sessions were planned so that the teeth were restored in pairs of two: two on the right and two on the left side, so as to allow bilateral occlusal contacts to be obtained at the end of each session. As a result, the increase in occlusal vertical dimension could be obtained without interfering with mastication, thus providing as much comfort as possible for the patient during treatment.
In the areas submitted to greater masticatory loads, such as the occlusal surface of posterior teeth and the palatal surface of incisors and canines, Filtek P60 resin was used, because of its high inorganic content, which is specific to these situations (Figures 3 and 4).
After the restorations were complete, multi-bladed burs, Sof-Lex Pop-On polishing discs (3M ESPE) and silicone points (Cosmedent, Chicago, IL, USA) were used for finishing and polishing (Figure 5).
Every direct restorative treatment requires dental professionals have advanced technical knowledge and superior dexterity. In addition, the direct technique employed in the current case—increasing the occlusal vertical dimension with resin composite—requires attention to the usual aspects related to adhesive systems when bonding artificial material to the surface of natural teeth. Following a previously validated protocol is of paramount importance to reducing the chances of failure and optimizing technical results. Among the steps that should be taken prior to treatment, it is possible to include the preparation of study models, diagnostic wax-ups and the preparation of restorative guides.
One of the characteristics of resin composites for direct restorations is that they undergo wear along their useful life as a result of the attrition generated during mastication. In young patients, follow-up visits should be scheduled over time to confirm that the occlusal vertical dimension obtained during treatment is maintained. When considerable wear is detected, the preparation of new restorations should be considered.
Restorations may be affected in the short-term if the patient's systemic health problem recurs. An acid pH value in the oral cavity causes erosion of the support structures and may lead to failure of the rehabilitation treatment.
SUMMARY OF ADVANTAGES AND DISADVANTAGES
The possibility of performing functional rehabilitation without cavity preparation or with minimal drilling of the remaining tooth structure is the main advantage of the technique herein described. In a young patient, preserving natural tooth structures may enable the future use of novel rehabilitation techniques to recover loss of occlusal vertical dimension.
The unpredictable durability of the suggested treatment is probably its main disadvantage. Resin composites may undergo substantial wear in large restorations of occlusal surfaces, as well as the fracture of thinner material layers.
This direct restorative technique is also more sensitive when compared with indirect techniques and, therefore, requires operators to take greater care and possess superior dexterity.
Eduardo Galia Reston, DDS, MSD, PhD, professor, Department of Restorative Dentistry, School of Dentistry, Lutheran University of Brazil, Canoas, RS, Brazil
Luciane Quadrado Closs, DDS, MSD, PhD, professor, Department of Orthodontics, School of Dentistry, Lutheran University of Brazil, Canoas, RS, Brazil
Adair Luiz Stefanello Busato, DDS, MSD, PhD, professor, Department of Restorative Dentistry, School of Dentistry, Lutheran University of Brazil, Canoas, RS, Brazil
Gustavo André Broliato, DDS, private practice, former graduate student, Restorative Dentistry Department, School of Dentistry, Lutheran University of Brazil, Caxias do Sul, RS, Brazil
Fábio Rafael Tessarollo, DDS, resident in Orthodontics, Department of Orthodontics, School of Dentistry, Lutheran University of Brazil, Canoas, RS, Brazil