Today, bulk-fill composites have become a recognised and effective solution for large cavities. They enable us to streamline the treatment process, saving valuable operative time, all while maintaining both robust mechanical characteristics and appealing aesthetics.
Posterior composites can fail and cause sensitivity due to various factors:
- Marginal Leakage: Gaps between the composite filling and tooth structure allow bacteria and fluids to infiltrate, leading to secondary decay and discomfort.
- Microleakage: Tiny particles and bacteria pass between the filling and tooth due to inadequate bonding or material shrinkage, causing sensitivity and potential damage.
- Polymerization Shrinkage: Composite materials shrink upon hardening, creating gaps if not managed properly, resulting in sensitivity and secondary decay risk.
- Inadequate Bonding: Incorrect bonding agent application leads to poor adhesion, causing gaps and sensitivity.
- Insufficient Curing: Improper light curing prevents the composite from achieving its optimal properties, resulting in sensitivity and shorter restoration lifespan.
- Secondary Decay: Poorly sealed composite edges enable bacteria to form new cavities beneath the filling, causing sensitivity as decay progresses.
- Cracking or Fracture: Composite fillings can crack or fracture in posterior teeth due to inadequate adaptation or strength, leading to discomfort.
- Inadequate Occlusal Adjustment: Improper bite adjustment after restoration can cause sensitivity and potential damage.
Bonding composite to amalgam should be avoided due to differences in material properties, chemical incompatibility, potential for weak bonds, marginal integrity issues, reduced clinical longevity, compromised aesthetics, and susceptibility to patient habits like teeth grinding or clenching. Instead, dentists typically prefer to remove amalgam entirely and bond composite to natural tooth structure for better results.
Below is a summary workflow of a case involving the replacement of posterior restorations.
The patient reported sensitivity to cold foods on the upper left side. Upon examination, we observed a composite restoration bonded to amalgam on tooth 26 and detected signs of marginal leakage on tooth 27.
Isolation using rubber dam.
Caries and an existing amalgam filling were removed.
The cavities were cleaned with air abrasion (AquaCare) 29 Micron Aluminium Oxide Powder.
The cavities were then ready for bonding procedures.
Selective enamel etch using 37% phosphoric acid for 30 seconds. This was then washed thoroughly with water for at least 60 seconds.
The LM Posterior Solo Instrument was used not only to fill and shape the cavities but also to measure the depths of each cavity. The instrument features intelligent markings, clearly denoting 4-5mm markings on its sharp edge, enabling dentists to promptly assess cavity depths and ensure they align with the recommended 4-5mm bulk fill guidelines for the composite material.
Apply adhesive to the tooth using a micro brush rubbing the bond in for 10 seconds and leaving to work for 20 seconds. Gently air dry for 5 seconds to remove the solvent. Light-cure for 20 seconds using Eighteeth Curing Pen.
A thin (0.5 mm) layer of flowable composite was applied to the dentine and cured.
The cavities were then ready to be restored with paste composite.
All the cavities were completely filled, extending to their uppermost points, using a packable bulk-fill material (Ecosite Bulk Fill, DMG). This provides a fast and reliable option especially as the bulk filled composite has a curing depth of 5mm.
Using the existing anatomical features as a guide, the broader tip of the LM Solo Posterior was used to pack the composite material against the cusps ensuring the instrument was following the same cusp inclination. The finer tip was then used to eliminate any excess material.
Using the pointed tip, the central fossa was placed which was used as a reference point to create the fissure patterns.
Using the pointy end of the LM Solo Posterior, I applied a brown coloured composite (Brown, DMG) to give the restorations a more natural finish and also to seal the fissures. When using coloured composite It’s important to note that less is more in this context. To remove excess coloured composite, a large microbrush was used, ensuring it remained primarily at the base of the fossae and within the sulci.
The composites restorations were again cured for a further 40 seconds.
A simple finishing and polishing protocol was carried out using ASAP step 1 and 2 and the eves occluflex.
Any other polishing spirals can be used to polish the restorations. It is important to polish all posterior composites to ensure no residual composite is left behind and improve the longevity of the restorations.
The rubber dam was removed and the occlusion was checked using articulating paper.
Immediate post op of the completed restorations.
One month recall.
Bulk-fill composites offer many advantages in dental restorative procedures compared to traditional incremental layering techniques. Here are some of the key advantages of bulk-fill composites:
- Efficiency: Bulk-fill composites can be placed in thicker layers (often up to 4-5 mm), which significantly reduces the number of increments needed to fill a cavity. This leads to shorter treatment times, making it more efficient for both the dentist and the patient.
- Depth of Cure: Bulk-fill composites are designed to have deeper curing capabilities, ensuring adequate polymerisation even in thicker layers.
- Minimised Air Inclusions: The reduced number of increments and improved flow characteristics of bulk-fill composites reduce the likelihood of air entrapment during placement, which can negatively impact the final restoration’s integrity.
- Patient Comfort: The reduced chair time can enhance the patient’s comfort and overall experience during the dental procedure.
- Versatility: Bulk-fill composites are suitable for a wide range of posterior restorations, including Class I, II, and occasionally Class V cavities. They can also be used for core build-up and as a base under other restorative materials.
- Clinical Predictability: When used correctly according to the manufacturer’s instructions, bulk-fill composites have demonstrated good clinical outcomes and longevity in posterior restorations.
It’s important to note that the success of bulk-fill composites depends on using the correct techniques, including adequate curing and proper finishing and polishing. It is imperative that clinicians should also consider the specific product’s characteristics and follow the manufacturer’s guidelines to ensure optimal results.
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