Example essay

Class I glass ionomer restorative resurfacing: an illustrated trial

Glass polyalkenoate systems (glass ionomer cements) have remarkable characteristics that make them valuable dental restoration-repair materials. They are hydrophilic, biocompatible, tooth-colored, and contain and release fluoride ions. Additionally, they form chemical chelating bonds with tooth structure, have a coefficient of thermal expansion similar to tooth structure, and are easily syringe-injected for precise placement in a prepared tooth. Resin-modified type glass ionomers have improved physical characteristics, making them suitable for use where higher wear resistance and breaking strengths are required. Changes in the size and distribution of glass particles also influence the utility of the various glass ionomers. An example is the “nanoionomer”.1

Over time, all glass ionomer restorative cements are subject not only to wear but also to erosion due to acidic influences in the mouth. This does not necessarily result in the need to completely replace glass ionomer restorations that have deteriorated somewhat. Frequently, glass ionomer restorations can be resurfaced using a bonded resin composite coating.2 This treatment can be considered by “long-term layering” repair.3 The restoration can be cut out, including mechanical undercut retention and the original material retained as the dentin replacement base. This brief illustrated report shows the resurfacing repair of an 8-year-old occluso-buccal restoration in a mandibular permanent molar. Resin-based composite resurfacing results are displayed at 47 months.


In September 2008, an 8.5-year-old woman underwent bite-mouth repair of her right mandibular first permanent molar. Eight years and 2 months later (December 2016), she was treated for an occlusal carious lesion of the adjacent second molar. The two teeth are shown preoperatively in Figure 1. Once the lower alveolar block anesthesia was performed and the restoration of the second molar completed, the rubber dam was moved to the first molar and this tooth was isolated. . The first molar was then repaired as follows (Figures 2 to 14).

Figure 1. After occlusal repair of the second molar, special attention was paid to this 8 year and 2 month old resin modified glass ionomer (RMGI) restoration.

Figure 2. The rubber dam was repositioned on the first molar. Wear and erosion are visible on the 8 year old glass ionomer restoration.

Figure 3. The peripheral enamel at the margins of the cavosurface has been roughened with a large round diamond bur.

Figure 4. A coarse-grained cylindrical diamond bur was used to cut the original restoration 1 to 2 mm and expose the walls of the new preparation. Note the mechanical clearance from the cavity walls.

Figure 5. Preparation completed for resurfacing. The residual RMGI serves as a dentin replacement coating / base.

Figure 6. A self-etching bonding agent was applied and stirred for 30 seconds, followed by exposure to the light beam for 10 seconds (traditional etching / rinsing / drying / gluing is another option).

Figure 7. The enamel replacement resin composite has been carefully injected so as not to incorporate air voids.

Figure 8. Exposure to light (1100 mW / cm2) was carried out for 20 seconds each of the buccal and occlusal aspects.

Graph 9. A large, round, slow-speed diamond bur shaped the occlusal surface.

Figure 10. A resin bonding agent glaze was painted over the restoration surface and peripheral enamel.

Figure 11. Immediately after the last exposure to the 20 second light beam.

Figure 12. The opposing sharp cusp has been smoothed out to avoid concentrated impact forces.

Figure 13. The occlusion was assessed and the necessary adjustments were made.

Graph 14. The resurfaced restoration of the first molar, 47 months after the operation and 12 years, 2 months after the initial dental repair.

Author’s Note: The brand names of the materials used in this technical demonstration have not been included in this report. The method works well for virtually any type of glass ionomer system used for dentin replacement that is combined with a suitable bonded resin composite coating. We consider the mechanical undercut to be important in acting as a form of additional retention, which helps fortify the material against occlusal and masticatory impact forces.

The references

1. Killian CM, Croll TP. Nano-ionomer dental repair in pediatric dentistry. Pediatrician Dent. 2010; 32 (7): 530-535.

2. Croll TP, Cavanaugh RR. Resurfacing of resin-modified glass ionomer restorations. Inside dentistry. 2009; 5 (1): 82-83.

3. Croll TP, Cavanaugh RR. Posterior resin-based composite restorations: a second opinion. J Esthet and Restor Dent. 2002; 14: (5) 303-312. doi: 10.1111 / j.1708-8240.2002.tb00526.x


Dr Killian is in private pediatric dentistry practice in Doylestown, PA. She received her DMD degree from the University of Pennsylvania and her specialty certificate in pediatric dentistry from St. Christopher’s Children’s Hospital in Philadelphia. Dr Killian is an adjunct associate professor of pediatric dentistry at the University of Pennsylvania and an affiliate clinic at the Children’s Hospital of Philadelphia. She is a member and former administrator of the American Academy of Pediatric Dentistry as well as a diplomat and past chair of the American Board of Pediatric Dentistry. She can be contacted at [email protected]

Dr Croll is a diplomat with the American Board of Pediatric Dentistry. He graduated from the Temple University School of Dentistry, and after 3 years in the US Army Dental Corps, he completed his training in pediatric dentistry at the University of Connecticut in 1978. Dr. Croll practiced in a private specialty practice of Pediatric Dentistry in Doylestown, Pennsylvania. , since 1978 and became Clinical Director of Cavity Busters Doylestown, LLC, in December 2018. He is currently Adjunct Clinical Professor of Pediatric Dentistry at the University of Texas Health Sciences Center at San Antonio and Clinical Professor of Pediatric Dentistry at Case Western School of Dentistry. He can be contacted at [email protected]

Disclosure: The authors are not reporting any disclosures.

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