Effects of Preventive Procedures on Dental Restorations

Many patients receive preventive dental hygiene procedures twice a year and periodontal maintenance procedures up to four times per year. The instrumentation technique and products selected by the dental hygienist can be beneficial or detrimental to the patient’s dental restorations. The dental hygienist needs to identify the restorative materials that are present before starting treatment. Restorations can be identified through reviewing radiographs, tactile detection and applying air to the surface of the restoration. Often times, a black line of metal may be apparent when an explorer is used on the restoration. Esthetic restorations may also reveal a dry, chalky appearance when air is applied.1

Preventive and maintenance procedures are often performed using a combination of hand and ultrasonic instrumentation, followed by polishing. It is important to use the combination that will be most effective for deposit removal, while causing the least amount of damage to restoration and tooth structure. There is conflicting evidence regarding the effect of scaling with hand instruments versus ultrasonic instrumentation and the amount of tooth structure that is lost in each case. Some studies report that scaling with hand instruments produces greater loss of tooth substance.2,23,24 However, other studies indicate that there is not a significant difference in the amount of tooth structure lost when comparing hand and ultrasonic instrumentation.25,26

There is potential for instrumentation with ultrasonic scalers and hand instruments to damage composite restorations (hybrid and microfilled), glass ionomers, laminate veneers and titanium implant abutments. When using ultrasonic instrumentation, the clinician needs to follow the safe practices of establishing proper water flow to prevent overheating, proper power needed for deposit removal, and proper adaptation of the side of the tip.21 Ultrasonics have the potential to alter the margins of amalgam restorations and fracture porcelain. In order to avoid damaging the restoration, the tips of scalers should never be directed into the junction where the enamel and restorative material meet.3

For clinicians who prefer to use air polishing systems, recent research shows air polishing may be more effective at plaque and stain removal than polishing with rotating cups and abrasive pastes.28,29 Sodium bicarbonate powders have been used traditionally. However, there are additional agents available for use with air polishers. These include glycine, calcium sodium phosphosilicate, calcium carbonate and aluminum trihyrdoxide powders.19 Clinicians should be familiar with the properties of each agent and understand the manufacturers’ respective recommendations. For example, due to the surface alterations that were observed visually and with a Scanning Electron Microscope, aluminum trihydroxide powder should be avoided on resin composites, resin-modified composites and around the margins of cemented restorations.4 In general, dental hygienists should avoid the use of air polishers on composite restorations.1

Fluoride application is beneficial for preventing recurrent decay near dental restorations. According to Artopoulou et al., 1.1% sodium fluoride (NaF) is the preferable choice for esthetic restorations. Sodium fluoride has been shown to cause less stain and deterioration of porcelain surfaces than 0.4% stannous fluoride (SnF2).5 Dental hygienists should also avoid the use of acidulated phosphate fluoride, which may cause alteration of the filler particles and discoloration of the resin. If fluoride mouthrinses are recommended for home care, avoid suggesting rinses that contain alcohol, which acts as a solvent for the BIS-GMA resin. This results in softening the material, which can increase roughness and stain.1

The use of CAD/CAM (computer-aided design and computer-aided manufacturing) restorations within dental practices has increased and dental hygienists will need to be familiar with their characteristics in order to properly maintain them.6 Some materials, such as e.max CAD lithium disilicate ceramic, have good abrasion resistance, but prophylactic pastes produced a reduction in translucency.7 In order to keep the restoration looking new and as natural as possible, it is important to follow manufacturers’ recommendations regarding the appropriate product to use for maintaining the restoration.1