Nowadays, dental resin composite restoration is becoming more popular than traditional materials such as amalgam due to improved aesthetics, tooth sparing preparation, lack of corrosion and etc. However, the inherent polymerization shrinkage of composites can produce a gap formation at the tooth-restoration interface [1]. Microleakage has been strongly associated with marginal gap and in vitro studies have associated the presence of secondary caries with microleakage [2]. This gap formation may develop into secondary caries.

Methods

Articles identified through an electronic search on MEDLINE®/Pubmed were limited to January 2000 to May 2015. The keywords “Gap Size” and “Secondary Caries or Caries” were selected and reviewed as per objectives. Only articles that referred composite material for experiments were included. After applying the inclusion criteria, the search yielded twelve publications. These studies either studied gap size or secondary caries around restoration using Tooth-resin composite specimens or occlusal splints containing human dentin samples. The sample size analyzed ranged from 0µm -1.025µm.

Results

Majority of studies concluded that gap size is not relevant in the development of secondary decay as long as caries risk is low and there is on fluoride release. When caries risk is high, even a gap size 68µm can lead to development of secondary caries. However, there was a consensus that large enamel gap size ranging from 100µm-500µm could lead to the development of dentin wall at the Tooth-resin composite interface.

Discussion

Secondary caries is the main reason to replace both resin composite and amalgam restorations. One of the possible etiologic factors for secondary caries development around resin composite restoration is microleakage, caused by a small gap between tooth-restoration interfaces. However Jorgensen and Wakumoto [3] found that secondary caries does not occur if gap size at the tooth- restoration interface is limited to 35-50μm; hence micro leakage would not lead to secondary caries.

Other studies [4,5] concluded that even larger gaps, ranging 250-400µm, have no influence on the initiation of secondary caries.

On the other hand, a clear relationship of gap size and secondary caries has been shown in [6]. A study from Nassar and Gonzalesz-Cabezas [7], found that as long as the gap size is small (35μm), there is no positive correlation between gap size and secondary caries development; however, larger gaps of approximately 500μm, could lead to development of secondary caries irrespective of micro leakage; however, larger gap size of approximately 500µm show a positive correlation between gap size and secondary caries.

Kuper et al. [8], claimed that the gap size may not be relevant as long as the caries risk is low, however, when the caries risk is high, even a gap size of 68μm may cause secondary caries to develop. This may imply that minimal gap size for developing secondary caries can be lower than what previously indicated in literature (>250 μm; [5]). The in situ study carried out by [9], showed that gap width affects secondary caries formation at the cavity preparation and restoration, but only in the absence of fluoride release. Since caries is a multi factorial disease, there are other important factors to be considered in the development of secondary caries. For example, oral hygiene, use of fluoride, frequency of sugar consumption, and cariogenic biofilm control will play an important role in developing recurrent caries. Kuper et al. [10], inferred that clinically, caries susceptibility of the patient may override the effect of gap size on secondary caries development. However, along with other important factors, it is clearly shown that the effect of gap formation between the tooth and the resin composite provides a favorable environment in developing secondary caries.

From the studies mentioned in this literature review, an exact threshold for developing secondary caries could not be achieved at this present time, but there is a trend that shows an increased likelihood of developing secondary caries as the gap size increases.

Conclusion

Our literature review concluded that the wider the gap between tooth and resin composite restoration material, the more likely secondary caries will develop unless caries risk is low, without absence of fluoride use. There is no consensus on the exact threshold of gap size to develop possible decay. Therefore, further studies will be needed in the future.

1. Eick JD, Gwinnett AJ, Pashley DH, Robinson SJ (1997) Current concepts on adhesion to dentin. Crit Rev Oral Biol Med 8: 306-335.
2. Lima FG, Romano AR, Correa MB, Demarco FF (2009) Influence of microleakage, surface roughness and biofilm control on secondary caries formation around composite resin restorations: an in situ J Appl Oral Sci 17: 61-65.
3. Jorgensen KD, Wakumoto S (1966) Occlusal amalgam fillings: marginal defects and secondary caries. Tandlaegebladet 70: 651-662.
4. Ozer L (1997) The relation between gap size, microbial accumulation and the structural features of natural caries in extracted teeth with class II amalgam restorations: A stereo-and polarized light microscopic study. University of Copenhagen, Denmark.
5. Mjör IA (2005) Clinical diagnosis of recurrent caries. J Am Dent Assoc 136: 1426-1433.
6. Totiam P, González-Cabezas C, Fontana MR, Zero DT (2007) A new in vitro model to study the relationship of gap size and secondary caries. Caries Res 41: 467-473.
7. Nassar HM, González-Cabezas C (2011) Effect of gap geometry on secondary caries wall lesion development. Caries Res 45: 346-352.
8. Kuper NK, Opdam NJ, Ruben JL, de Soet JJ, Cenci MS, et al. (2014) Gap size and wall lesion development next to composite. J Dent Res 93: 108-113.
9. Cenci MS, Tenuta LM, Pereira-Cenci T, Del Bel Cury AA, ten Cate JM, et al. (2008) Effect of microleakage and fluoride on enamel-dentine demineralization around restorations. Caries Res 42: 369-379.
10. Kuper NK, van de Sande FH, Opdam NJ, Bronkhorst EM, de Soet JJ, et al. (2015) Restoration materials and secondary caries using an in vitro biofilm model. J Dent Res 94: 62-68.

Citation: Hyun L, Chitre S, Gill K, ChitreS (2016) A Brief Review on the Relationship Between Gap Size of Composite Restoration and Secondary Caries. Dent Adv Res 1: 103. DOI: 10.29011/2574-7347.100003