Anterior contact deprogramming

22 June 2021
4 min read

Siddarth Gupta presents a case in which he treated a patient suffering from anterior tooth wear with composite restorations, achieving a functional and aesthetic transformation.

Tooth surface loss is a multifactorial condition which can frequently go unnoticed or be left untreated. Pathological wear can be attributed to erosion, abrasion, attrition and abfraction. Often, however, the role of the airway is overlooked. It can play a significant part in the patient’s life, not only affecting their oral health but also their general wellbeing. Management of the worn dentition can be challenging, with treatment needing a lifetime of care. However, additive composite can help provide a significant improvement in both function and aesthetics, as well as protection against further deterioration.

A 39-year-old lady presented with concerns regarding her anterior dentition . She felt her teeth were getting smaller and chipping. Following a sleep study, the patient was diagnosed with sleep apnoea, with initially more than 50 episodes of apnoea per hour. Over 30 episodes per hour are considered to be severe. Sleep apnoea has been linked to nocturnal bruxism, chemical attack related to reflux and xerostomia. Provision of a continuous positive airway pressure (CPAP) machine reduced the number of episodes to less than five per hour.

Clinical examination
Analysis of the patient’s diet revealed a high intake of carbonated and sugary drinks. She was not aware of any parafunction habits, either daytime clenching or night-time grinding.

A full clinical examination was undertaken. The temporomandibular joint was examined and found to be normal, although the patient had a history of a click in both joints. There was no tension or tenderness to load testing, or muscle tenderness. She had a class IV anterior clinical erosive (ACE) classification score. Non-restorable secondary caries on the lower left second molar was discovered and subsequently required extraction. The patient’s periodontal health was good, as was her oral hygiene. A diagnosis was made of localised anterior tooth wear due to diet and likely reflux from obstructive sleep apnoea.

The treatment options consisted of further monitoring, complex orthodontic and possible orthognathic surgery to correct the narrow maxillary arch and posterior cross bites, or a restorative-only compromise. This would help to restore the anterior teeth for cosmetic and functional gain and allow the posteriors to ‘dahl’ into position.

The patient opted to take the restorative-only approach. Initial preventative management consisted of diet modification and brushing with high-strength Duraphat sodium fluoride 5000ppm toothpaste.

Impression taking and muscular deprogramming
Maxillary and mandibular two-stage spaced polyvinyl silicone impressions were taken using Kulzer Provil novo Putty and Light body, along with a WhipMix Denar Facebow record to facilitate accurate mounting. A Lucia Jig was placed on the patient for 20 minutes to allow muscular deprogramming. Bimanual manipulation was employed to seat the mandible in centric relation. This was recorded with WhipMix Denar Wax and models were mounted onto a Denar Mark 320 semi-adjustable articulator.

An additive wax-up was carried out on the maxillary and mandibular anterior teeth, canine to canine. The wax-up was performed with the aid of 2D smile design using Apple Keynote. It was transferred to the patient’s mouth with a silicone impression and methacrylate temporary material. Occlusion, speech and aesthetics were assessed, and minor adjustments were made where required.

Once the patient was happy with the trial smile, the restorations were planned. Due to the ease of maintenance, cost and repairability, the decision was made to use composite resin instead of porcelain. Prior to the start of treatment, shade determination was carried out by placing composite ‘buttons’ on the central incisors before dehydration could take place. A Bio- Emulation Polar_Eyes polarised image was taken to confirm the shade.

Using a split-dam technique, appropriate isolation was carried out with Unodent non-latex heavy rubber dam, from the maxillary first premolar to the contralateral first premolar. A Provil novo Putty silicone impression of the wax-up was used to create a palatal stent for the maxillary dentition. The use of a palatal matrix can be highly beneficial in class IV restorations by making composite layering simpler. Crucially, in this case, it facilitated a precise replication of the functional palatal surfaces that were created in the wax-up and finalised in the trial smile.

The teeth were prepared with air abrasion using aluminium oxide with a Rønvig Dental Dento-Prep sandblaster. Selective enamel etching was carried out for 30 seconds with phosphoric acid and a universal bonding agent was applied.

Composite placement for balanced contact and canine lateral guidance
Kulzer Venus Pearl composite was chosen for this case. Incisal shade Clear (CL) was used for the palatal shell and final enamel layer, and Opaque Medium Chromatic (OMC) dentine shade and A2 body were used in a polychromatic layering technique. Venus Pearl has been shown to exhibit superior durability and aesthetic characteristics. Kulzer Signum liquid modelling resin was used to enhance handling and sculpting. After the layered restorations were completed on the maxillary dentition, final curing was carried out through glycerine gel to prevent emergence of an oxygen-inhibited layer.

Due to the lower aesthetic requirements for the mandibular dentition, a different approach was adopted for composite placement. An impression of the wax-up was taken using Kulzer Memosil 2 clear silicone. The isolation and preparation of the mandibular teeth was carried out in the same way as the maxillary arch. The adjacent teeth were isolated with PTFE tape. The composite was injected into the clear silicone and immediately transferred to the tooth and cured for 40 seconds. The composite was refined prior to restoring the next tooth in the sequence.

Following composite placement, occlusal adjustments were carried out. Fremitus was checked to ensure bilateral contact, balanced contact on protrusion and lateral guidance on the canines. Given the greater length of the canine roots, a slightly heavier contact on these teeth was preferred.

Final polishing and occlusal adjustment
Due to operator and patient fatigue, refinement and polishing was carried out one week later. Shofu Brownie stones with an NSK speed-increasing handpiece and Sof-Lex discs were used to define the primary anatomy. Kulzer Venus Supra polishers were used to create secondary anatomy such as the labial grooves, and carry out an initial polish. Tertiary anatomic touches were made, followed by a final polish using diamond polishing spirals.

With contact only on the anterior dentition, the build-ups act like a deprogrammer. This allows seating of the temporomandibular joint into centric relation. Only a minimal amount of occlusal adjustment was required at the end of treatment, as the decision to plan the case in centric relation was made from the outset, instead of waxing up using the patient’s existing intercuspal relation.

At the six-month review the composite restorations were holding up extremely well, having retained the shine and lustre of the initial polish and showing no signs of deterioration. Following a short period of adjustment, the patient has gained greater confidence showing her teeth when smiling and eating without fear of further damage to her teeth.