The debate about polishing goes on. But by using instruments and abrasives selectively designed to conserve tooth structure and restorative materials, we can encourage clients to keep their appointments for the esthetic benefits they receive, while at the same time safely removing calculus, plaque, and associated toxins with minimal worry about loss of tooth structure.
Many dental hygienists are concerned about the risk of damage to teeth due to instrumentation. We are aiming toward less aggressive forces that might cause undue wear of the tooth surface while still removing stain, disease-producing substances, and deposits that inhibit thorough plaque removal during home care.
The American Dental Hygienists’ Association takes the position that polishing should not be considered a routine procedure but should be offered only when a dental hygienist or dentist determines a specific need for it. ADHA justifies its position on the “little therapeutic benefit” produced by polishing. A true prophylaxis, prevention of disease, is attainable in many cases without polishing, since calculus is removed by scaling, plaque and debris can be removed by brushing, and stain and rough surfaces are not always present. Polishing fissured surfaces before placement of sealants is no longer recognized as necessary, again, because there are other methods of plaque removal. Polishing also removes the surface layer of the tooth, thereby reducing the fluoride content and the bulk of the tooth structure. Furthermore, enamel absorbs professionally applied fluoride just as well without polishing as with polishing.
Air polishing with sodium bicarbonate is beneficial for removal of heavy stain, endotoxins, and plaque and debris in areas of difficult access, but air polishing is contraindicated with several medical conditions where sodium ingestion or aerosol inhalation should be avoided and with the presence of most restorative materials, exposed dentin, or exposed cementum, which can suffer significant abrasion.
In addition to the general risks and benefits of polishing, ADHA warns of the potential for abuse of the public’s ignorance when equating polishing with prophylaxis. Polishing with or without superficial scaling when more work is necessary might be incorrectly billed as a prophylaxis to the detriment of the client and the client’s insurance company. This can lead to progression of undiagnosed periodontal disease. Bacteria can proliferate trapped in pockets under tight gingival margins that have undergone only superficial improvement in health. Finally, the dental hygienist’s access through the tightened gingival margins will be hindered once accurate diagnosis and treatment commence.1
Some analysts do question the scientific data behind scaling and polishing.
Beirne, Forgie, Worthington, and Clarkson reviewed eight studies on scaling and polishing and concluded insufficient evidence for their risks and benefits. Although some studies showed significant reduction in “plaque, gingivitis, pocket depth, and attachment change” with increasing frequency of scaling and polishing, there was too much risk of bias in the studies to support any conclusions on the effectiveness of utilizing the procedures or any particular frequency regimen. A point of concern in one of the studies is that periodontal patients in a recare program showed no significant difference in “plaque, gingivitis, and attachment loss” over a one-year period between one side of the mouth receiving scaling and polishing and the other side, which did not receive treatment.2 However, one may wonder whether this method of study can provide an accurate assessment of the value of the removal of deposits when the untreated side of the mouth is conveniently placed as a source of infection for the treated side.
There is evidence that the cumulative effects of dental hygiene care can cause significant loss of tooth structure, even when there is no attempt to be aggressive about removing deposits. Rühling, Wulf, Schwahn, and Kocher studied a simulation of 10 years of periodontal maintenance recare by comparing the long-term abrasive effects of polishing alone, polishing plus curettes, and polishing plus ultrasonic scalers on bovine teeth in vitro. The effects were measured on cementum, enamel, and four types of filling material. The study demonstrated that there is a significant loss of material due to instrumentation. Cementum is least resistant to material loss with polishing plus curettes; however, enamel is least resistant to polishing plus ultrasonic scalers. The rate at which polishing plus curettes led to loss of cementum corresponds with encroachment into dentin in a human patient’s fourth decade of life, threatening the comfort and vitality of affected teeth. Excessive wear of filling materials leads to roughness and loss of marginal and structural integrity. As a result of these findings and their relevance to function of the dentition, these authors recommend reducing the aggressiveness of periodontal therapy and recare.3
Although dental hygienists should take care to minimize loss of tooth structure during instrumentation, there is reason to question whether surface attrition occurs as rapidly in vivo as it does in vitro. There is literature on the effects of pH and salivary concentrations of calcium, phosphate, and fluoride on remineralization of carious lesions, but we do not know the effects of these conditions on the abraded tooth surface. Hayakawa, Yoshinari, Sakae, and Nemoto report the ability of hydroxyapatite to precipitate on a number of surfaces that are immersed in an electrolyte solution saturated with calcium phosphate.4
Similarly, experimental methods of remineralization by Forsback, Areva, and Salonen for occluding dentinal tubules shows silica, dissolved from forms of glass, can enhance the deposition of calcium phosphate on dentin surfaces in conditions simulating normal biological fluids. Such enhancement is related to the increased concentration of calcium ions.5 Note that this effect is a surface mineralization, rather than the subsurface remineralization that we know to happen in decalcified areas in the earliest stage of the caries process.
Given this improved mineralization on a tooth surface, we should look forward to studying the potential for surface mineralization without enhancement. If the process occurs, it might counteract the abrasive effect of polishing to some degree, making encroachment into dentin slower than calculated by in vitro studies of the cumulative effects of instrumentation, which occur without several months of immersion in an oral environment between treatment simulations.
Indeed, there are distinct reasons to polish that despite abrading tooth or restorative surfaces may decrease the overall attrition in teeth over the long term. Lu, Roeder, and Powers justify polishing restorations to promote longevity as well as esthetics. In addition to promoting healthy periodontal tissues and resisting stain, a polished, smooth surface will cause less attrition of natural tooth surfaces the restoration contacts during chewing. They also demonstrate that the choice of restorative material and the choice of polishing system both affect the surface roughness, with the polishing system more of a factor.6 As an example of polishing to reduce long-term attrition, Al-Wahadni and Martin demonstrated that unglazed porcelain surfaces will produce greater wear on opposing surfaces than will a glazed surface. They concluded that after adjusting porcelain crowns, the operator should polish with a diamond paste to create a finish that is most like a glazed surface in its abrasive qualities. Other polishing methods leave the adjusted surface as abrasive as an unfinished porcelain surface. Removing the glaze layer of porcelain leaves a surface that is more abrasive due to both surface roughness and the nature of the exposed particles.7
Miller stresses the value of polishing and scaling, including ultrasonic scaling for health in general and for all-porcelain crowns in particular to maintain the esthetic attributes these restorations provide. She suggests polishing prior to using the ultrasonic scaler to ensure all of the polish is removed by the subgingival flow of water. She points out the importance of disrupting the oral flora as an important clinical strategy toward the goal of attaining or maintaining oral health.8
Haynes suggests polishing prior to probing and scaling. This makes the latter procedures more efficient and consequently more effective in achieving the primary goal of removing the causative agents and aggravating factors of poor oral health. An explanation of this philosophy to clients can help them integrate the esthetic concerns, to which they are accustomed, with the health concerns dental hygienists promote.9
Ferracane stresses the importance of choosing a polishing agent appropriate to the restorative material in order to achieve ideal esthetics and minimize plaque accumulation for maintenance of periodontal health. The smallest size of abrasive particles in the last step of polishing will usually produce the smoothest finish; however, each type of restorative material needs individualized assessment for the best polishing system. Furthermore, surfaces of some restorations may not be accessible to a particular polishing system due to the size and shape of the polishing points.10
Technological advances are providing instrumentation techniques that conserve more of the natural and restored tooth surfaces while removing unesthetic and pathogenic deposits. Petersilka, Bell, Häberlein, Mehl, Hickel, and Flemmig found that changing the physical properties of air-polishing abrasives could help reduce abrasive effects on root surfaces while still removing extrinsic stains.
Abrasive forces of sodium bicarbonate can be adjusted with the amount of water flow and distance from the instrument to the tooth, but not to the extent of removing stain without the risk of damaging cementum and dentin by “cutting, fatigue, and brittle fracture.” However, softer particles made of organic and inorganic salts with a shape and size to minimize abrasion to the root surface are able to reduce risk to the tooth while removing deposits.11
Braun, Krause, Frentzen, and Jepsen demonstrated similar amounts of root surface removed when comparing the Vector ultrasonic system with standard magnetostrictive ultrasonic tips when using these tips in vitro to remove plaque and associated toxins. The Vector system recommends a polishing fluid containing hydroxyapatite or an abrasive fluid containing silicone carbide, and has a resonating device that deflects vibrations directed toward the tooth surface, thereby minimizing forces that remove tooth substance. The purpose of polishing using the polishing fluid is to remove plaque and endotoxin, which builds up on the surface of cementum, with minimal removal of the cementum. Less force directed at the tooth surface results in reduced damage to the root surface, as fluid dynamics remove the plaque. This can provide effective control of inflammation after thorough debridement of calculus and before new deposits of calculus begin to form.12 In another study, the same authors found that the Vector system can remove calculus as efficiently as more widely used ultrasonic tips when the curette tips and abrasive fluid are used.13
Dental hygienists can provide treatment that provides the standard of care toward health of our clients while providing the esthetic benefits for which many of those clients initially seek dental hygiene services. By using instruments and abrasives that are selectively designed to conserve tooth structure and restorative materials, we can encourage clients to keep their appointments for the esthetic benefits they receive.
At the same time, with the continuing refinement of our instruments and materials, we can safely remove the calculus, plaque, and associated toxins with minimal worry about loss of tooth structure.
References
1 American Dental Hygienists’ Association. The American Dental Hygienists’ Association (ADHA) takes the following position regarding polishing procedures. Access Jan. 2003; 17(1):20-21.
2 Beirne P, Forgie A, Worthington HV, Clarkson JE. Routine scale and polish for periodontal health in adults. Cochrane Database of Systematic Reviews, Jan. 25, 2005(1); CD004625. Retrieved Jan. 14, 2006 on http://www.ncbi.nlm.nih.gov.
3 Rühling A, Wulf J, Schwahn C, Kocher T. Surface wear on cervical restorations and adjacent enamel and root cementum caused by simulated long-term maintenance therapy. Journal of Clinical Periodontology 2004; 31:293-298.
4 Hayakawa T, Yoshinari M, Sakae T, Nemoto K. Calcium phosphate formation on the phosphorylated dental bonding agent in electrolyte solution. Journal of Oral Rehabilitation Jan. 2004; 31(1):67-73.
5 Forsback AP, Areva S, Salonen JI. Mineralization of dentin induced by treatment with bioactive glass S53P4 in vitro. Acta Odontologica Scandinavica Feb. 2004; 62(1):14-20.
6 Lu H, Roeder LB, Powers JM. Effect of polishing systems on the surface roughness of microhybrid composites. Journal of Esthetic and Restorative Dentistry 2003; 15(5):297-304.
7 Al-Wahadni AM, Martin DM. An in vitro investigation into the wear effects of glazed, unglazed, and refinished dental porcelain on an opposing material. Journal of Oral Rehabilitation June 1999; 26(6):538-546.
8 Miller KR. Creating and maintaining beautiful smiles. RDH March 2005; 25(3):72-76, 96.
9 Haynes K. To polish or not to polish? RDH Jan. 2004; 24(1):60-61.
10 Ferracane JL. Surface roughness of packable restorative resins polished with various systems. Journal of Esthetic and Restorative Dentistry 2005; 16(1), 48.
11 Petersilka GJ, Bell M, Häberlein I, Mehl A, Hickel R, Flemmig TF. In vitro evaluation of novel low abrasive air polishing powders. Journal of Clinical Periodontology Jan. 2003; 30(1):9-13.
12 Braun A, Krause F, Frentzen M, Jepsen S. Removal of root substance with the VectorTM-system compared with conventional debridement in vitro. Journal of Clinical Periodontology Feb. 2005; 32(2):153-157.
13 Braun A, Krause F, Frentzen M, Jepsen S. Efficiency of subgingival calculus removal with the Vector™-system compared to ultrasonic scaling and hand instrumentation in vitro. Journal of Periodontal Research Feb. 2005; 40(1):48-52.
