Recent Advances in Preventive Resin Restoration (PRR)

 

L. Sri Varsha

 

ABSTRACT:

Aim and objective: to review about the recent advances in preventive resin restoration. Background: Preventive resin restoration (PRR) is a thin, resin coating applied to the chewing surface of molars, premolars and any deep grooves of the teeth. It consists of an enamel sealant with a resin filling. If caries is present in one area or parts of pits and fissures, that particular area of caries is restored and fissures are protected with sealants. Reasons for review: Newer materials and techniques may help in reducing the risk of early failure in difficult to seal teeth and to also improve the retentiveness and strength of the material.

 

 

 

INTRODUCTION:

Preventive resin restoration(PRR) consists of a thin, resin coating applied to the occlusal surface of molars, premolars and deep grooves. Most decays begin in the deep grooves. Thus, teeth with this condition are difficult to clean and becomes more susceptible to caries. PRR protects the tooth by sealing the deep grooves and creating a smooth, easy to clean surface. By this way, the teeth is protected from decay for several years, provided they are checked for chipping and wear at regular dental checkups. Sealants are effective caries-preventive agents to the extent they remain bonded to teeth.

 

Dental caries is due to the imbalance between loss and gain of minerals from a tooth surface.^[1]The loss of minerals from our teeth occurs from the bacteria from the foods and producing acids, whereas the tooth gains minerals from our saliva and fluoride that is present within our mouth^[1] which over a period of time becomes a tooth decay.

 

 

 

 

 

 

Fissure sealants are a preventive treatment that is part of the minimal intervention dentistry approach to dental care.^[2] This approach facilitates prevention and early intervention, in order to prevent or stop the dentalcaries process before it reaches the ends stage of the disease, which is also known as the "hole" or cavitation of a tooth.^[2]

 

 

How are sealants applied?

History of PRR:

There have been many attempts made within past decades to prevent the development of caries, in particular occlusal caries as it was once generally accepted that pits and fissures of teeth would become infected with bacteria within 10 years of erupting into the mouth.^[3,4] One of the first attempts to prevent occlusal caries occurred as early as 1905 by Willoughby D. Miller.^[4] Miller, a pioneer of dentistry, was applying silvernitrate to surfaces of teeth, chemically treating the biofilm with its antibacterial functions against both Streptococcusmutans and Actinomycesnaeslundii, which are both carious pathogens.^[1,2,3,4] Silvernitrate, which was also being practiced by H. Klein and J.W. Knutson in the 1940s, was being used in attempt to prevent and arrest occlusal caries^[3][5]. In 1921, T.P. Hyatt, a pioneer researcher, was the first person to recommend prophylactic odontotomy (preventive operation)^[3][5][7]. This procedure involved creating Class 1 cavity preps of teeth that were considered at risk of developing occlusal caries, which included all pits and fissures^[1][3][5]. The widening of the pits and fissures were then filled with amalgam ^[3][5][7]. In 1929, Bödecker attempted to prevent occlusal caries by cleaning the pit and fissures with an explorer and then sealing the pits and fissures with dentalcement, such as oxyphosphate cement ^[1]. It was in 1955, that M.G. Buonocore gave insight to the benefits of etching enamel with phosphoricacid.^[3][4][5] His studies demonstrated that resin could be bonded to enamel through acid etching, increasing adhesion whilst also creating an improved marginal integrity of resinrestorativematerial.^[1][3] It was this bonding system that lead to the future successful creation of fissure sealants.^[4][7] In 1974, glassionomercement fissure seals (GIC) were introduced by J.W. McLean and A.D. Wilson.^[8]

 

Advances in PRR:

·      ACP releasing sealant

·      Amorphous calcium proteins

·      Release fluoride

·      Tooth colour

·      Enamel LOC

·      Self etching

·      Light cure

·      Release fluoride

·      Natural white

·      Enamel wetbond

·      No BISPHENOL

·      No BISGMA

·      Fluoride releasing

·      Light cured

 

Newer materials may help reduce the risk of early failure in difficult-to-seal teeth. Use of an intermediate bonding layer between enamel and sealant has been shown effective in the face of major saliva contamination in our previous lab studies^[9][10][11] as well as a clinical study.

 

 

 

A new adhesive fissure sealant, which consisted of a solution of 3% 2-hydroxy-3-β-naphthoxypropyl methacrylate in methyl methacrylate (MMA), poly-MMA powder and an oxidizedtri-n-butyl borane, a polymerisation initiator, was developed.

 

Resin based sealants:

·      First generation: set with UVcuring.^[11] They are no longer marketed.^[12]

·      Second generation: chemical-curing (autopolymerized).^[12,13]

·      Third generation: visiblelight-cured.^[12,13]

·      Fourth generation: contain fluoride.^[12,13]

 

There was a controversy related to the safety of Bisphenol A (BPA), concerns have been raised over the use of resin based sealants. BPA is a xenoestrogen, which  mimics the relative bioactivity of estrogen, a female sex hormone. Pure BPA is rarely present in dental sealants, however they may contain BPA derivatives. There is very little research about the potential estrogen-like effects of BPA derivatives. A transient presence of BPA in saliva has been reported immediately following placement of some resin based sealants.The longest duration of salivary BPA was 3 hours after placement, so there is little risk of chronic low-dose BPA exposure. The currently available evidence suggests that there is no risk of estrogen-like side effects with resin based sealants.^[12]

 

Glass Ionomer sealants:

GIC materials bond both to enamel and dentine after being cleaned with polyacrylic acid conditioner.^[3] Some other advantages GIC’s have is that they contain fluoride and are less moisture sensitive, with suggestions being made that despite having poor retention, they may prevent occlusal caries even after the sealant has fallen out due to their ability to release fluoride.^[3][12][14]

 

·      Moist tolerant pit and fissure sealants- there has been a significant advancement in resin-based sealants with the development of moisture tolerant chemistry. Traditional sealants were hydrophobic where a completely dry field is required. Recently a new advanced resin based sealant with the development of moisture control chemistry, a hydrophilic moisture tolerant resin based sealant named Embrace WetBond has been developed. A study by Joseph P.O Donnell in 2008 shows the moisture-tolerant Embrace WetBond sealant had a 95% success after 2 years which is comparable to other sealant studies where teeth that were difficult to isolate were excluded.^[15,14]

·      Fluoride releasing pit and fissure sealants- fillers are added to resin sealants which contain fluoride. In a clinical evaluation of 2 years, Helioseal-F is applied in school children at risk of caries. Out of 431 fissure sealants complete retention found on 77% while 22% were partially lost, and 1% were completely lost.

 

In a study conducted in puducherry,

·      Microleakage of three different restorative material (flowable composite, nanocomposite, conventional sealants) used as pit and fissure sealants was found to be higher for flowable composite and least for conventional sealant. The nanocomposite values were intermediate, i.e. flowable composite> nanocomposite > conventional sealant.

·      Penetration depth of the three different dental materials used as pit and fissure sealant was higher for nanocomposite, and least for flowable composite. The conventional sealant ranks second, i.e. nanocomposite > conventional sealant > flowable composite.

·      The study revealed that nanocomposite was found to be an excellent dental material for penetration in deep pits and fissures, though it exhibits mild microleakage. Hence, it can be recommended for use in dental patients, as pit and fissure sealants, which is a core strategy for prevention of caries.^[16,17]

 

CONCLUSION:

Regular maintenance and sealant addition when necessary is important in long-term caries protection after sealant placement. Much better effectiveness data will result if sealants are used on teeth with a true predilection to caries. Better materials and better use of bonding agents with sealants will improve overall effectiveness on all teeth,particularly on those teeth now thought of as difficult to seal.Use  of  sealants  has  proved  to  have  good  results.  For prevention  of  dental  caries  in  pit  and  fissure,  sealants were introduced.  There  is  evidence  suggesting effectiveness  of  sealants  when  compared  with  no sealants.  Sealants  prevent  bacteria  growth  which  causes caries.  Biomaterials  to  seal  pit  and  fissure  should  present with  the  simple  application  method,  biocompatibility,  low viscosity  and  good  surface  retention  and  low solubility.^[18]And  to  improve  this  biomaterial,  more  laboratory  should be  developed.

 

REFERENCES:

1.     Featherstone, JDB (2008). "Dental caries: A dynamic disease process". Australian Dental Journal. 53 (3): 286–91.

2.     White J.M., &Eakle W.S. Rationale and Treatment Approach in Minimally Invasive Dentistry. Journal of the American Dental Association, 2000.

3.     Avinash, J.; Marya, C.M.; Dhingra, S.; Gupta, P.; Kataria, S.; Meenu; Bhatia, H. P. (2010). "PitandFissureSealants: AnUnusedCariesPreventionTool" (PDF). Journal of Oral Health and Community Dentistry. 4 (1): 1–6.

4.     Feigal, R. J.; Donly, K. J. (2006). “The use of pit and fissure sealants”. Pediatric Dentistry. 28 (2): 143–150.

5.     https://scholarworks.iupui.edu/bitstream/handle/1805/2078/view.pdf

6.     Donovan, T. E.; Anderson, M.; Becker, W.; Cagna, D. R.; Carr, G. B.; Albouy, J.; Metz, J.;Eichmiller, F.; McKee, J. R. (2013). "Annual Review of selected dental literature: Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry". The Journal of Prosthetic Dentistry. 110 (3): 161–210.

7.     Zero, D. T. (2013). "How the introduction of the acid-etch technique revolutionised dental practice". The Journal of the American Dental Association. 144 (9): 990–994.

8.     Ahovuo-Saloranta, A; Forss, H; Walsh, T; Hiiri, A; Nordblad, A; Mäkelä, M; Worthington, HV (28 March 2013). "Sealants for preventing dental decay in the permanent teeth". The Cochrane Database of Systematic Reviews. 3(3): CD001830.

9.     Hitt JC, Feigal RJ: The effect of moisture contamination on sealant technique. J Dent Res 68:[Abst 1040} 1989.

10.   Hitt JC, Feigal RJ: Use of a bonding agent to reduce sealant sensitivity to moisture contamination: An in vitro study. Pediatr Dent 14:41-46, 1992.

11.   Borem LM, Feigal RJ: Reducing microleakage of sealants under salivary contamination: digital-image analysis evaluation. Quintessence Int 25:283-89, 1994.

12.   Ahovuo-Saloranta, A; Forss, H; Walsh, T; Hiiri, A; Nordblad, A; Mäkelä, M; Worthington, HV (28 March 2013). "Sealants for preventing dental decay in the permanent teeth". The Cochrane Database of Systematic Reviews. 3(3): CD001830.

13.   Hiremath, SS (15 August 2011). Textbook of Preventive and Community Dentistry. Elsevier India. pp. 428–432.

14.   Seth, S (2011). "Glass io nomercement and resin-based fissure sealants are equally effective in caries prevention" (PDF). JADA. 142 (5): 551–552.

15.   Murnseer C, Rosentritt M,Handel G.Three body wear of fissure sealants. J Dent Res.2007;86:abstract 417

16.   Antoniadou M. Setting efficiency of resin based sealants. Abstract 212. Sept 15, 2005; Amsterdam, Netherlands.

17.   S,Singh, RK Pandey. An evaluation of nanocomposites as pit and fissure sealants in child patients. Journal of Indian Society of Pedodontics and Preventive Dentistry, Vol. 29, No. 4, October-December, 2011, pp. 294-299

18.   Mertz Fiarhurst EJ, Fairhurst CW, Williams JE et al. A comparative clinical study of two pit and fissure sealants; 7 year result in Augusta , Georgia.

 

 

 

Accepted on 31.05.2018        © RJPT All right reserved

Research J. Pharm. and Tech 2019; 12(1): 382-384.