Revisiting endodontics – Kate Scheer

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  Posted by: Dental Design      20th August 2019

Nothing lasts forever. Enamel is the hardest material in the human body, being 96% crystalline calcium phosphate.[1]However, it is attacked on a daily basis and cannot be regenerated by the body, so when oral hygiene is not sufficiently maintained it can be eroded and the risk of a patient developing dental caries increases.

As practitioners are aware, dental caries enables bacteria to attack the living core of the tooth: the pulp. This leads to infection and abscesses in the root of the tooth. This, in turn, can undermine the structural strength of the tooth, lead to bone loss around the root, affect drainage and further spread infection. Successful endodontic treatment disinfects the root canal system and can help save the tooth.

However, restoration materials are not indestructible, and are subject to the same conditions that wore through their enamel predecessors. Chipping, wear, cracking and displacement can all provide points of ingress for bacteria. Having not been grown as part of the tooth, restoration materials have the added requirement of needing to maintain adhesion to natural tissue. If the seal between the filling and tooth breaks down, bacteria can build up along the perimeter of the restoration or beneath it, leading to further decay of the tooth –  secondary (aka recurrent) caries.[2]Secondary caries and discolouration of resin-based composites are some of the most common reasons for the replacement of restorations.[3]

Material differences

While dental amalgam is currently being phased out for environmental reasons, it is still used within the NHS (on patients over 15) and will be commonly encountered for many years to come. Amalgam restorations are a common and reliable treatment, but although they are generally long-lasting, there have been less enduring mixes. For instance, low-copper amalgams that were in use prior to 1963 were subject to corrosion.[4]

Composites were introduced in the 1960s and have proven popular, largely due to their aesthetic qualities. Early composite restorations had durability issues that could see posterior composites serve for less than a decade. Polymer shrinkage and adhesion failures were not uncommon. However, this has been an area of continuous development and modern composites have greatly improved. The rate of progress and variety of composites in use do make accurately accessing longevity difficult, but recent systematic reviews place the annual failure rate in the low single digits (1-5%).[5]Polymer shrinkage has not been totally eliminated as an issue, which can lead to other complications that include tooth flexure, undue stress on the tooth, and post-operative pain.[6]The finish and final polish are important factors influencing longevity, with small surface defects adversely affecting the service life of a restoration.[7]Bruxism and other parafunctional habits can also cause the fracture, wear and – in a minority of cases – loss of a natural tooth or restoration.[8]

The choice of restorative material used affects plaque build up, with resin-based materials accumulating more cariogenic plaque than amalgam, silicate cement or glass ionomer restorations.[9]The same bacteria responsible for caries – chiefly Streptococcus mutans (S. mutans) – are believed to degrade dental resin composites and adhesives over time, to a lesser or greater extent depending on their particular chemical composition. Why exactly this is the case is still being examined, though chemical vulnerability to acidity produced by S. mutansand other cariogenic bacteria is likely the largest factor.[10]The presence of a restoration may actually shift the ratio of different species of bacteria in the oral cavity, making it more or less cariogenic in nature. Amalgam has intrinsic antibacterial properties due to its metallic composition.[11]

Piezoelectric instruments

Piezoelectric equipment can be utilised for endodontic applications, such as removing root canal filings and fractured instruments. In addition to offering great precision, an advantage of piezoelectric instruments is that they will not cut soft tissues, as the frequencies used to cut hard and soft tissue are different.[12]Piezoelectric handpieces facilitate access to the root tip and reduce the risk of root perforation, helping to prevent complications.[13]Passive ultrasonic irrigation is generally regarded as superior to traditional syringe and needle irrigation for eliminating pulp tissue and dentine debris. Combining conventional irrigation with the use of an ultrasonic instrument may further improve results.[14]

Compatible with the Proxeo Ultra and the Pyon piezo scaling units, the enhanced W&H scaler tip range offers a variety of useful piezo instruments ideal for endodontics. From removing surgical detritus and gutta-percha, to non-cutting tips designed for rinse activation – there is a tool suitable for just about every endodontic eventuality.

In many cases where a restoration has failed, it is possible to repair or replace the prosthesis and preserve the tooth for years to come. With appropriate material selection and execution of treatment, endodontic restorations can last a lifetime.


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[1]Jayasuha, Baswaraj, Navin H., Prasanna K. Enamel regeneration – current progress and challenges. Journal of Clinical & Diagnostic Research. 2014; 8(9): ZE06-ZE09. 15, 2019.

[2]When a filling needs to be replaced. JADA.2005; 136(7): 1062. 15, 2019.

[3]Mjör I. Clinical diagnosis of recurrent caries. JADA. 2005; 136(10): 1426-1433. 15, 2019.

[4]Shenoy A. Is it the end of the road for dental amalgam? A critical review. Journal of Conservative Dentistry. 2008; 11(3): 99-107. 15, 2019.

[5]DeMarco F., Collares K., Correa M., Cenci M., de Moraes R., Opdam N. Should my composite restorations last forever? Why are the failing? Brazilian Oral Research.2017; 31(suppl. 1): 92-99. 15, 2019. 

[6]Shenoy A. Is it the end of the road for dental amalgam? A critical review.  Journal of Conservative Dentistry. 2008; 11(3): 99-107. 15, 2019.

[7]Velo M., Coelho L., Basting R., Amaral F., France F. Longevity of restorations in direct composite resin: literature review. RGO Revista Gaúch de Odontologia. 2016; 64(3): 320-326. 15, 2019. 

[8]DeMarco F., Collares K., Correa M., Cenci M., de Moraes R., Opdam N. Should my composite restorations last forever? Why are the failing? Brazilian Oral Research.2017; 31(suppl. 1): 92-99. 15, 2019. 

[9]Mjör I. Clinical diagnosis of recurrent caries. JADA. 2005; 136(10): 1426-1433. 15, 2019.

[10]Bourbia M., Ma D., Cvitkovitch D., Santerre J., Finer Y. Cariogenic bacteria degrade dental resin composities and adhesives. Journal of Dental Research. 2013; 92(11): 989-994. 15, 2019.

[11]Nedeljkovic I., De Munck J., Slomka V., Van Meerbeek B., Teughels W., Van Landuyt K. Lack of buffering by composties promotes shift to more cariogenic bacteria. Journal of Dental Research. 15, 2019.

[12]Deepa D., Jain G., Bansal T. Piezosurgery in dentistry. Journal of Oral Research and Review.  2016; 8(1): 27-31. 15, 2019.

[13]Seedat H., van der Vyver P., de Wet F. Micro-endodontic surgery – part 1: surgical rationale and modern techniques.South African Dental Journal.2018; 73(3): 146-153. 15, 2019.

[14]Mozo S., Llena C., Forner L. Review of ultrasonic irrigation in endodontics: increasing action of irrigating solutions. Med Oral Patol Oral Cir Bucal.2012; 17(3): 512-516. 15, 2019.

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