The treatment of a patient with extensive tooth wear presents with particularly complex challenges, however experience the Sydney dentist may be. This arises primarily due to determining the source of often a multi-factorial etiology, to the diagnosis of tooth wear and the definitive management of the patient. Because of this, Complex Aesthetic and Functional Rehabilitation will be needed.
Historically the management of patients presenting with extensive tooth wear was with conventional fixed prosthodontics. This would involve preparation with crowns on the teeth where tooth structures were already compromised. This would increase the biomechanical risk to the dentition due to the reduction of tooth structures, which negatively impact the structural rigidity of the teeth.
Additionally a conventional approach could result in a loss of pulpal vitality of the teeth. Teeth requiring fixed prostheses have a 6-11% requirement for endodontic treatment. This approach is more invasive and is irreversible.
With the development of adhesive bonding, we have the means of restoring the dentition in a much more conservative manner with an additive approach and this case will describe the concepts involved in a complex rehabilitation using both direct and indirect restorations with minimal biological risk to the patient.
Table 1: Advantages of adhesive restorations
| Retention form and resistance form not relevantEnamel bonded – predictableConservative and minimally invasiveDecreased endodontic riskMaximizing remaining tooth structures
Clinical Case Overview
Age: 41 year old
Chief complaint: Short nature of her teeth causing poor quality and esthetics, as well as the occasional bilateral masseter muscle tenderness.
Oral examination: Intra-orally the tooth surface loss was generalized, involving all the teeth in both arches and extended into dentine. Anteriorly, there was also thinning and chipping of the incisal edge resulting in reduced clinical crown height.
The diagnosis requires a need to identify the factor(s) contributing to tooth wear, which may be difficult due to often a multi-factorial etiology. This is important to identify to preserve the remaining dentition and to improve the long-term prognosis of any restorative treatment completed.
The patient was diagnosed to have tooth wear due to tooth erosion that had occurred when she was bulimic, with a secondary etiology of bruxism. Chronic exposure to acidic substrates had led to exposure of the dentine, chipping of the teeth, and was complicated with the parafunctional habits of the patient.
Patients that present with generalized tooth wear often do not display a loss of OVD due to the loss of tooth surfaces occurring at a slow rate, which allows time for alveolar compensation. In cases where the surface loss is active and rapidly progressing this may lead to loss of occlusal vertical dimension as alveolar compensation may not be keeping up to the same rate. In occlusion, the patient appeared to have a decreased lower face height due to a loss in occlusal vertical dimension, which had not fully been compensated for by alveolar compensation (Figure 2).
The objectives of treatment are to:
- Improve dentofacial aesthetics.
- Restore occlusal vertical dimension and improve occlusal function establishing a stable position of maximum intercuspation with bilateral simultaneous occlusal contacts.
- Restoring and protecting structural compromised and exposed dentinal teeth structures with minimally or no preparation designs.
- Prevent further tooth erosion.
The extra-oral examination allows
assessment of the amount of incisal display while the upper lip is relaxed (Figure 3) and while the patient is talking and smiling (Figure 4). This reveals that there was insufficient display of the teeth, and that there was the potential to lengthen the incisal edges of the maxillary teeth.
Following a comprehensive intra-oral clinical assessment including diagnostic photographs, study casts were taken and mounted on a semi-adjustable articulator.
A diagnostic wax up (Figure 5, 6) was undertaken, with the requested esthetic changes communicated to the dental ceramist. The occlusal prescription included contouring the wax build-ups to provide bilateral even contacts in retruded contact position.
Upon completing the work-up the treatment plan decided upon in consultation with the patient included:
- Mandibular – direct resin composite build-ups on teeth Nos 22-28 and coverage of dentinal exposed areas on teeth Nos. 19, 30, 31
- No-preparation restorations on teeth Nos. 2, 5-12
- Minimal invasive onlay preparations on previously restored teeth Nos. 3, 14, 15
Mandibular Direct Composite Resin Build-ups
Each tooth was prepared by abrading with 27 micron Aluminum Oxide and a total etch adhesive technique (Optibond Solo Plus, Kerr Dental) was utilized. Placement of resin composite (Herculite Ultra, Kerr Dental) was accomplished with the aid of a silicone matrix formed from the palatal anatomy established from the diagnostic wax up (Figure 7). Resin composite was carefully adapted in layered increments, no greater than 1.5 mm per increment. The use of the matrix allows the placement of composite to form the palatal contour and incisal length of the teeth as planned from the diagnostic waxup (Figure 8). This will allow minimal adjustment at completion of the restrations.
Maxillary Indirect Restorations
Prep-less or additive restorations were planned for the majority of the maxillary teeth as these were in a lingualized axial position and furthermore needed to be lengthened for ideal esthetics. Hence there would be no need to prepare the teeth to achieve the desired outcome. Additionally by not preparing the teeth the restorations would be bonded to mainly enamel apart from areas that had dentine exposure on the incisal/occlusal surfaces. The success and predictability of bonding to enamel are major factors in terms of longevity and durability of the restorations.
In a 12-year study of 583 veneers 7.2% or 42 veneers failed. With those veneers bonded to dentin and teeth with preparation margins in dentin were approximately 10 times more likely to fail than those bonded to enamel.
Teeth that were previously restored had the restorations removed and the preparations completed to allow a path of insertion for onlays to be inserted (Figure 9). In this case a bonded functional esthetic prototype (BFEP) was spot-etched and bonded into position utilising putty indexes made from the diagnostic wax-ups (Figure 10). This allows the patient to assess the “trial smile” prior to completing the final restorations (Figure 11). This transitional stage allows time for the patient to accept the proposed new smile but also to be able to assess the occlusal changes from the increase in occlusal vertical dimension and occlusal stability over a period of weeks or even months.
The provisional restorations were removed with careful attention to remove areas that had been spot-etched and bonded with a bur. The remaining tooth structures were air abraded with 27 micron aluminum oxide.
The final restorations were fabricated with pressed lithium disilicate (e.max – Ivoclar Vivadent) materials using a B1 LT ingot (Figure 12).
The lithium disilicate restorations were individually placed to assess marginal fit and contact points. The restorations were then placed with a clear try in gel to display to the patient prior to permanent cementation, who then gave approval for the final cementation.
Each restoration was etched with 4.5% hydrofluoric acid for 20 seconds, followed by cleaning of the chemical salts by rinsing and insertion into an ultrasonic bath with distilled water. After air drying each restoration was then silanated for more than 60 seconds.
As the ceramic restorations are thin, and have minimal retention due to minimal or no preparation, cementation requires the restorations to be adhesively bonded with resin cement. A strong, durable resin bond provides high retention, improves marginal adaptation reducing microleakage, and increases fracture resistance of the restored tooth and the restoration.
The teeth were adhesively bonded with a total etch technique (Optibond Solo Plus, Kerr Dental) and restorations bonded with a light cure resin cement (NX3 Nexus, Kerr Dental) for the anterior teeth, and dual cure resin cement (NX3 Nexus, Kerr Dental) for the posterior onlays which were thicker in cross-section.
The restorations were then adjusted and finished with ceramic polishing and finishing techniques. The margins were finished into an “infinity margin” (Figure 13). Once the margins were no longer detectable with an explorer, they were polished with rubbers and diamond polishing pastes. The occlusion was evaluated and adjusted in centric occlusion, lateral and protrusive movements and finally in the chewing envelope.
Due to the nocturnal bruxism habit a full maxillary occlusal splint was fabricated with careful instructions on it use.
The aim of managing the worn dentition should be to determine the etiological factors and institute an appropriate preventive program to protect the remaining tooth structures whilst restoring function, occlusal stability and esthetics. Treatment planning involves understanding the etiological factors involved, to the planning of the steps involved with the reconstruction of the dentition for both functional and esthetic requirements. A minimally invasive or prep-less approach is preferred and the use of
direct and/or indirect restorations can be utilized in reconstructing the lost tooth structures in an additive approach.
The author thanks Mr. Brad Grobler (dental ceramist) for the technical and artistic expertise of restorations included in this article.
- Extensive wear of tooth structures
- Facial view of patient with reduced occlusal vertical dimension
- Repose position of patient – lips at rest
- Full smile with minimal display of teeth
- Maxillary Diagnostic Waxup
- Mandibular Diagnostic Waxup
- Silicone matrix of diagnostic waxup allowing a template to allow buildup of resin composite
- Composite resin buildups carried out individually to template
- Occlusal view of maxiallary teeth demonstrating no preparation on majority of teeth and the removal of old restorations
- Bis-Acryl Resin Provisional restorations
- Trial smile with provisional restorations
- Lithium disilicate restorations on model and demonstration of incisal length increase
- Completed restorations on maxillary teeth
- Retracted frontal view of maxillary lithium disilicate restorations and mandibular direct resin composite
- Smile view of completed restorations.