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Ceramic restorations on Discoloured stumps around the gingival tissues

A tooth can discolour for a lot of reasons. If you ask a Sydney dentist about this, you will be advised that teeth could discolour due to age, food, beverage, medications, trauma, dental caries or exposure to highly staining compounds.

A tooth fitted with a porcelain fused to metal crown may stain after prolonged exposure to the metal. This results in an unsightly discoloured stump that often reflects and affects the gum tissue. Teeth with discoloured stumps are very unattractive. It gives the patient a smile that looks dirty, old and diseased, especially since the stained appearance reflects on the soft tissue or gums too.

It is a frustrating problem because even if you place the margins at a subgingival level, the problem still remains. When we encounter a problem like this in the clinic, we suggest a few things to the patient:

1. Internal bleaching. An initial remedy for the discoloured stump that has spread to the gingival tissues is to perform an internal bleaching procedure. This is most appropriate for root canal treated teeth, with effectiveness that is quite unreliable.

2. Opaque restoration. A more definite solution that we provide involves masking or covering the discoloured stump with an opaque restorative material or composite resin. Using Kolor +- Kerr Dental we overlay the darkened area to mask the unappealing area so that it does not reflect on the crowns and on the gum tissues.

This kind of remedy is applicable for root canal treated teeth, teeth receiving dental crowns, bridges and veneers. It may be performed on porcelain-fused-to-metal crowns, all-porcelain crowns or even zirconium crowns. The result you receive is a natural-looking teeth restoration, the appears good as new. The teeth will appear beautiful, healthy and clean.

Discoloured stumpsDiscoloured stumpsCeramic restorationsCeramic restorations

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Sonic activated composite in a full arch build-up for extensive tooth wear

Extensive multi-surface tooth wear is common in several people and your Sydney dentist will explain how it may easily be caused by a different things:

  • Chemical erosion. When there is acid regurgitation or the presence of a naturally acidic oral environment, the teeth may be severely worn away so that the bite collapses as teeth height is reduced on the maxillary and mandibular jaw.

  • Bruxism. Night grinding or bruxism is a paroxysmal habit observed during night slumber, but may also be experienced in the day. It is an involuntary problem that involves the over-clenching of the teeth that often leads to wear facets and damage.

  • Malocclusion. When the patient’s bite is wrong or is misaligned, this disharmony can cause damage to the teeth. This is common with people with cross-bite, deep bite and edge-to-edge bite. The upper and the lower teeth contact each other, in damaging fashion so that teeth become excessively worn away.

  • Ideally, this issue is resolved by installing dental crowns and bridges on all the teeth to restore the bite and the appearance of the teeth. This would be acceptable when not much damage has been incurred but when very little tooth surface is left to work with, retention for the prosthetics is highly compromised.

    Dr. Chris Ho follows a different approach and it is explained in detail in the attached post. In lieu of invasive and expensive crowns, composite resin is provided to restore the worn teeth. Utilizing a template, a specialized bonding adhesive and reinforced composite resin, the patient is given a better reason to smile.

    Advantages of getting a sonic-activated composite full-arch build-up:

Complex Aesthetic and Functional Rehabilitation with an Additive Minimally Invasive Restorative Approach

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 

ADHESIVE RESTORATION

                        Retention form and resistance form not relevantEnamel bonded – predictableConservative and minimally invasiveDecreased endodontic riskMaximizing remaining tooth structures

 

Clinical Case Overview

Gender: Female

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.

 

Diagnosis

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).

loss in occlusal vertical dimension

Figure 2


The objectives of  treatment are to:

  1. Improve dentofacial aesthetics.
  2. Restore occlusal vertical dimension and improve occlusal function establishing a stable position of maximum intercuspation with bilateral simultaneous occlusal contacts.
  3. Restoring and protecting structural compromised and exposed dentinal teeth structures with minimally or no preparation designs.
  4. Prevent further tooth erosion.

 

Treatment

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.

extra-oral examination

Figure 3

extra-oral examination

Figure 4

Following a comprehensive intra-oral clinical assessment including diagnostic photographs, study casts were taken and mounted on a semi-adjustable articulator.

diagnostic wax up

Figure 5

diagnostic wax up

Figure 6

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
  • Maxillary
  • 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.

27 micron Aluminum Oxide

Figure 7

27 micron Aluminum Oxide

Figure 8



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.

putty indexes

Figure 9

 

putty indexes

Figure 10

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.

trial smile

Figure 11

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).

lithium disilicate

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.

infinity margin

Figure 13

Due to the nocturnal bruxism habit a full maxillary occlusal splint was fabricated with careful instructions on it use.

 

Conclusion

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.

 

Acknowledgements

The author thanks Mr. Brad Grobler (dental ceramist) for the technical and artistic expertise of restorations included in this article.

 

Figure Descriptions

 

  1. Extensive wear of tooth structures
  2. Facial view of patient with reduced occlusal vertical dimension
  3. Repose position of patient – lips at rest
  4. Full smile with minimal display of teeth
  5. Maxillary Diagnostic Waxup
  6. Mandibular Diagnostic Waxup
  7. Silicone matrix of diagnostic waxup allowing a template to allow buildup of resin composite
  8. Composite resin buildups carried out individually to template
  9. Occlusal view of maxiallary teeth demonstrating no preparation on majority of teeth and the removal of old restorations
  10. Bis-Acryl Resin Provisional restorations
  11. Trial smile with provisional restorations
  12. Lithium disilicate restorations on model and demonstration of incisal length increase
  13. Completed restorations on maxillary teeth
  14. Retracted frontal view of maxillary lithium disilicate restorations and mandibular direct resin composite
  15. Smile view of completed restorations.

PORCELAIN VENEER PROVISIONALISATION

As a Sydney dentist, when I teach veneer provisional fabrication I teach a few different methods.

  • Direct buildup – a very small dot of etch is placed on the tooth in the mid-labial section and then bond is applied generously over the remaining preparation including the etched area and non- etched areas. This will allow sealing of the dentine so there is no sensitivity. Composite is then directly placed and sculpted into position to simulate the anatomy. This is best for a single or minimal amount of veneers. Please remember after removal of the provisional, a bur must be run over the etched area to remove any remaining composite that may be still bonded in the spot.
  • Bis-acryl provisionalisation conventional method. Using a putty key the temporary material is placed into the putty and placed over the prepared teeth. This is then removed and trimmed and cemented into position with temporary cement. This can be difficult due to the fact that these temporaries are thin and can break upon removal. It is recommended that a clear temporary resin cement like TempBond NE is used, as using an opaque cement can lead to very opaque looking veneer causing concern for the patient.

TempBond NE - sydney dentist

  • Shrink Wrap: Firstly the preparations are cleaned with chlorhexidine, and then a generous amount of desensitizer is used over the teeth, as this protocol does not involve cementation of the temporary veners. Using a putty key the temporary bis-acryl resin material (e.g. Protemp – 3M Espe, Luxatemp – DMG, Integrity- Denstply) is placed into the putty and placed over the prepared teeth, and as this polymerises the material undertoes shrinkage which “Shrink wraps” the temporary veneers onto the prepared teeth. Any excess is carefully removed best with multi-fluted carbide burs.

Shrink Wrap - sydney dentist

  • Spot Etch and Shrink Wrap: This is exactly the same technique as the shrink wrap but we add the spot- etch technique where avery small dot of etch is placed on the tooth in the mid-labial section and then bond is applied generously over the remaining preparation including the etched area and non- etched areas. The shrink-wrap technique then allows for the temporary material to bond to the etched area and the rest of the temporary is wrapped onto the teeth.

 spot-etch temporisation - sydney dentist

Each technique has advantages and disadvantages, however my favoured technique is the spot etch and shrink wrap technique as this ensures that the patient does not lose their temporary. Just remember that it can be more difficult to remove due to this being etched onto one specific area, so warn the patient, and also remember to go over the etched area with a bur upon removal of the temporaries to ensure that there is no remaining composite or adhesives stuck to the tooth. Once I have done this I like to use the Prepstart(air abrasion 27 micron Aluminium Oxide at 40 psi) to clean the tooth and prepare for adhesive processes.

prep start - Veneer - Sydney Dentist

Katana Zirconia (Noritake) translucent multi-layered zirconia

 

 

When a Sydney dentist is faced with an important cosmetic problem on a patient, one of the things he makes sure to do right is to pick the right shade. This is determined, by matching the existing teeth and making certain that the shade is appropriate to the complexion.

 

Matching the color and choosing the right shade for the restoration is important because the results and the overall satisfaction of the patient depends on this. A patient comes into a Sydney dentist’s office to get better smile and if the smile does not look natural and even, he will not be happy. The success of every case will rely on how happy the patient is with the results and sometimes it will all be about choosing the right restorative material.

Katana Zirconia

There has always been the concern with veneering porcelain chipping from a traditional zirconia crown, and the use of monotlithic full contour zirconia has recently become extremely popular to a Sydney dentist due to the high physical properties of these materials.

Historically it has always been the veneering (fedspathic) porcelain failing with fracturing or chipping. The trade off was always the poor aesthetics that followed due to the dense polycrystalline structures.

Recently, Noritake has released a full contour zirconia restoration using the new Katana Zirconia ML, a gradational multilayered zirconia disc with four layers of color–35% enamel, 15% of the first gradation layer, 15% of the second gradation layer and 35% dentin–that offers the look of layered porcelain. The pre-colored multilayered shades provide esthetic results without manual dipping or staining and eliminate additional material costs. KATANA Zirconia ML discs are available in three shades: A-Light, A-Dark and B-Light (KATANA HT–a high translucent mono-colored zirconia–is also available in three shades: HT10, HT12 and HT13). So far this material exceeds the aesthetics of other full contour zirconias, so look out for this material.