Abrasiveness of an Air-Powder Polishing System on Root Surfaces in Vitro

Abrasiveness of an air-powder polishing system on root surfaces in vitro

Mette S. Agger, DDSVPreben Hörsted-Bindslev, DDSTOle Hovgaard,

Objective: The purpose oí Ihis study was tc evaluate the abrasiveness of a new air polisher on roof surfaces. Method and materials: Fifty extracted human teeth were air polished for 5 seconds. Results: Ali root surfaces showed a circular defect visible wifh fhe naked eye. Scanning elecfron microscope examination showed smooth crater wails and a few open denfin fubules, but most seemed fc be obliterated. Laser profilomefry of the exposed areas revealed defecfs wifh an average depth of 484 ym, whereas fhe unexposed root surfaces showed irreguiarifies wifh an average depth of 323 gm. The depths of fhe abraded areas were evaluafed in relafion fo the values for the unexposed surfaces, and an average depth of 161 |jm was found.The difference befween the exposed and unexposed surfaces was statisticaliy significanf. Conclusion: The presenf sfudy indicates that the air polisher has a strong abrading effect on exposed roof surfaces and should therefore be used with caution on patients with gingival retractions. (Quintessence Int 2001:32:407-411 )

Key words: abrasiveness, air polishing, exposed roof surfaces

Sound, mature enamel has been shown to be resis- CLINICAL RELEVANCE: Air polishing should be per- tant to air polishing and polishing with pumice with- formed wifh caufion on exposed root surfaces. out significant signs of abrasion lesions,^^ whereas air polishing on white spot lesions and enamel (where the prisms have been cut or ground) left an eroded he most common method used for tooth polishing surface.* Tis a rotating rubber cup and pumice. This method Several studies have demonstrated that the air pol- is often disappointing when attempting to remove very ishing device removes significant amounts of calculus, adherent stains and can be time-consuming and sound dentin, and cement,^'"'^ and furthermore, surface fatiguing for the dentist. To meet the demands for changes have been observed in restorative materials.'^•'•' more efficient and time-saving tooth polishing, alter- The abrading effect on root surfaces was shown in a native instruments have heen developed. Among study by Atkinson et al,' who found that the air pol- these, the air polisher operates hy directing a slurry of isher removed an average of 636.6 |im of root struc- high-pressure water, air, and sodium bicarbonate ture after exposure for 30 seconds. The 30 seconds against the tooth surface. would be the total amount of exposure time if the In vitro and in vivo studies comparing rubber cup patient was maintained on a 3-month recall for 15 and pumice with air polishing have found air polish- years with a 0.5-second blast from the device at each ing to be the most efficient and time-saving method visit. The abrading effect on root structure has been for removal of tooth stain and dental plaque.'-" confirmed in later studies.^.«'» and Kontturi-Narhi et al" found that cement covered with plaque showed greater abrasive changes after air pohshing than air-

'Research Associate, Department of Dental Pathology, Operative Dentistry, polished surfaces free of plaque. and EndodontJcs, Royal Dental College, Faculty ot Heallh Sciences, Gingival traumas have been recorded as a side University of Aartijs, Denmark. effect when the air poiisher is used.''=" Due to the 'Associate Professor, Departmenl of Dental Pathology, Operative Deniislry, cervical location of stain and piaque accumulation, and Endodonlics, Royal Dental College, Faculty of Health Sciences, soft tissue trauma is dift'icult to avoid. University oí Aartijs, Denmark, Kontturi-Narhi et al" found that the most erosive ^Assistant Clinical Professor, Department of Dental Pathology. Operative changes were seen in inftamed gingiva, and that the Demistry and Endodontics, Royal Dental College, Faculty of Health Sciences, University of Aarhus, Denrrark. severity of the changes was related to the periodontal Reprint requests: Dr Preben Horsted-Bindsiev, Department of Dental health status. In vivo studies showed no lasting differ- Pathology Operative Dentistry, and Endodontics, Royal Dental College, ence in gingival trauma between air polishing and University of Aarhus, Vennelyst Boulevard 9, DK 8O0O Aarhus C, Denmark. rubber cup treatment, but immediate post-treatment E-mail: [email protected]

407 Quintessence International • Agger et al

The powder used for air polishing was supplied by the manufacturer. Tbe basic ingredient of the powder was sodium hydrogen carbonate, with addition of an orange flavor. A standard setting was used: The hand- piece was secured by a clamp to a metal stand, and eacb tooth was fixed with wax to a plastic cube and secured by a clamp. Tbe distance between tbe hand- piece nozzle and the tootb surface was 4 mm, with a preparation angle of 90 degrees. Tbe root surface was exposed for 5 seconds. After treatment, the teeth were removed from the plastic cube and rinsed with water to remove any excess sodium bicarbonate powder. All teeth were Fig 1 PR0PHYfie>!2, ttie air poiisher. profilometcr-scanned directly on the root surface with an optical profilometer (Micro focus 1080, UBM Messtecbnik).'" Next to the air-polisbed area, ati untreated root surface area of the same size as the air- polished area was profilomcter-scanned as a control. By random selection, 10 teeth were rinsed, dehydrated in alcohol, critical point dried, coated with carbon fol- evaluation sbowed an increase in gingival irritation lowed by a coating with 10 nm of platin, and exam- after air polishing.'-'^ ined in SEM. Recently, a modification of the previous air polisber Spray pressure of the air-ahrasive device without was introduced (PROPHYflex2, KaVo Dental) [Fig 1). powder and of the dental unit air-water syringe (A- The new instrument bas a Multiflex connection that dec) was measured hy a manometer (EMPEO) with a enables the practitioner to use it on all units, and com- custom-fit adaptor made hy tbe Technical Department pared to older air-abrasive instruments, the new at the Royal Dental College in Aarhus, Denmark. A device is easy to operate. The manufacturer describes computer statistical package (SPSS 8.0, SPSS) was the device as an efficient instrument for stain and used for statistical analysis. Means, standard deviation, plaque removal. Furtbermore, tbe device is recom- and ranges were calculated, and the data were ana- mended for polishing after calculus removal, cleaning lyzed using Student's paired i-test. enamel surfaces prior to fissure sealing, and preparing enamel cavities for befter bonding of restorative materials to enamel. RESULTS The purpose of the present study, by use of scanning electron microscope (SEiVI) and laser profilome- Tbe exposed area of all teeth showed a circular defect try directly on the root surface, was to evaluate the of approximately 2 mm in diameter (Fig 2). SEM abrasiveness of a new air polisher on exposed root revealed smeared crater walls where most dentin surfaces. tubules seemed to be obliterated (Fig 3). The profilometer scan showed a crater-like penetration with the deepest point centrally located (Fig 4) and an METHOD AND MATERIALS average depth of 484 pm, witb a range of 191,3 to 917 ym (SD = 196). The unexposed root surfaces showed Fifty fully developed buman teeth were chosen from a irregularities from 109.6 to 592 pm (SD = 153), with collection of extracted teeth and stored in 1% an average deptb of 323 pm. The depths of the cblorhexidine; all tooth types were represented. The abraded areas were evaluated in relation to the unex- teeth were examined under a macroscope (Wild posed root surfaces, and an average deptb of 161 pm M420) at x80 magnification and met the following was found (SD = 126). Tbe difference in depth mea- criteria: (1) the root surface showed a clinically sound surements ranged from -48 to 494 pm. surface without caries or fillings, although some root The values of eacb tooth were found by subtracting surfaces were abraded; (2) the surface was intact and tbe surface measurements on the unexposed root sur- showed no marks from the extraction forceps; (3) face from the surface measurements of the exposed there was no visible calculus, but variable degrees of area. One negative value was seen, meaning that one discoioration; and (4) the chosen area on tbe root sur- tooth showed surface irregularities deeper than the face was witbout fiber-inserted cementum. exposed irregularities. The difference between exposed

408 Volume 32, Number 5. 2001 Agger et ai

Fig 2 Scanning electron microscope stiowing a circular detect Fig 3 Scanning electron microscope of ttie surface of ttie after air polistiing tor 5 seconds (Original magnilicalion x4S). smeared crater wali. (Original magnification x1850).

155 [j

Fig 4 Prcfiiometerscan of ttie ai>potished area showing a circuiar defeot witii the deepest pcint centraliy iocated. and unexposed surfaces was statistically significant studies of surface alterations have used different meth- (P< 0.00001). ods to describe the abrading effect of air-abrasive Input pressure of air and water into the air polisher devices. Repiicas have heen weighed to find the amount and syringe was 4.1 and 2.0 ban, respectively. Output of lost root structure/" replicas of the tooth surface spray pressure at the nozzle ranged from 3.10 to 3.15 before and after treatment have been compared in ban-(mean = 3.11; SD = 0.02) for the air polisher and SEM," radioactive teeth have been treated to estimate from 3.40 to 3.50 barr (mean = 3.46; SD = 0.05) for the amount of lost root structure/'^" or the heights of the air-wat er syringe. rephcas have been measured.^ When laser-profilometry is used, a more precise abrasion depth may be found, because the measurements are done directly on the DISCUSSION tooth surface. Furthermore, the profilometer is able to level the scanned area horizontally, therefore eiiminat- Mechanical stain removal is a result of an abrasive ing the measuring probletns of curved surfaces. action on the surface, resulting in a more or less pro- The present results sbowed an average abrasion of nounced loss of surface structure depending on the 161 pm when the device was used for 5 seconds in a cleaning method and treatment time.'' stationary set up. Depth measurements ranged from The purpose of this study was to investigate the abra- -48 to 494 pm. The difference in abrasiveness might siveness of a new air polisher on root surfaces. Laser be caused by the difference in mineralization, and profilometry can be performed directly on the tooth therefore relative hardness, and hy varying degrees of surface and seems to be a very suitable technique for surface roughness. If only the exposed root surface quantifying variations on the tooth surface. Former bad been examined without subtracting the variations

Quintessence International 409 • Agger et al

on the unexposed root surface, the average ahrasion exposed root surfaces compared with former studies of depth would be 484 pm, therefore over-estimating the the abrading effects of conventional tooth cleaning true abrading efiect of the device. Comparing the methods. The device should be used witb caution on exposed root surface to the unexposed root surface pafients witb gingivai retractions and should be sup- gives a more precise measurement of the abrading plied with a warning that describes the potential effect of tbe air-polisbing device. abrading effeet on exposed root surfaces. Compared to the clinical use of the air polisher, where the bandpiece is swept across the surface, a stationary blast as used in tbe present study will increase ACKNOWLEDGMENTS tbe amount of tissue abraded. However, in a case of beavy stain accumulafion, the operator tends to dwell The aulhors wish to thank Jörgen Serup, Head of Ihe Department of Dermatológica! Science, Lovens Keniiske Fabrikker, Ballerup, for a longer period of time, and there might be an Denmark, for use of the laser prnfilonieter, and Jens Keiding for his overlap of the treated areas resulfing in a cumulative technical assistance. blast time of more than 5 seconds. The treatment time of 5 seconds was chosen to make the study compara- hle to other studies."^" REFERENCES The data from the measurements of the spray pressure indicate that the air-abrasive device used witbout 1. Weaks LM, Lescher NB, Barnes CM, Holroyd SV. Clinical evaluation of the Prophy-Iet as an instrument for routine powder bas a spray pressure at tbe nozzle tbat is lower removal of tooth stain and plaque. I Periodont Í984;55: compared witb a conventional dental air-water syringe. 486-488. Tbis illustrates tbat tbe abrading effect of tbe air-abra- 2. Berkstein S, Reiff RL, McKinney JF, Killoy WJ. Supra- sive device is due to the sodium bicarbonate particles. gingival root surface removal during maintenance proce- The findings from the present study should he com- dures utilizing an air-powder abrasive system or hand pared with the abrasiveness of the conventional scaling. J Periodont 1987;58:327-329. method by using rubber cups and pumice for stain 3. Strand GV, Raadal M. The efficiency of cleaning fissures with an air-polishing instrument. Acta Odontol Scand removal. Stookey^' studied tbe abrasive action of tbis 1988;46:113-lt7. method on enamel and dentin, and found the ruhher 4. Barnes CM, Rüssel CM, Gerbo LR, Wells BR, Bames DW. cups to be a gentle propbylactic metbod on dentin, Effeets gf an air-powder polishing system on orthodonti- removing 1.57 jim/10 mm'/lO seconds. Later studies cally bracketed and banded teeth. Am J of Orthod Derto- bave confirmed the insignificant removal of tooth facial Orthop 1990;97;74-81. structure hy use of the ruhber cups method.^^-^' 5. Boyde A. Airpolishing effects on enamel, dentine, cement Thus, even though the measuring methods differ and bone. Br Dent J 1984;156:287-29L between previous studies and tbe present study, tbe 6. Gerbo LR, Lacefield WR, Bames CM, Russell CM, Enamel insignificant abrasion found after rubber cups polish- roughness after air-powder polishing. Am Dent J 1993; ing and the significant abrasion seen in the present 6:96-98. 7. Atkinson DR, Cobb CM, Killoy WJ. The effect of an air study justify the conclusion that the air polisher powder abrasive system on in vitro root surfaces. ] removes significantly more dentin than rubber cup Periodontol 1984;55:13-I8. polishing within the same time of exposure. 8. Petersson LG, Hellden L, ¡ongebíoed W, Arends J. The Besides the abrading risks, occupational aspects effect of a jet abrasive instrument (Prophy Jet) on root sur- also must be considered. In spite of high volume aspi- faces. Swed Dent J 1985;9:193-199. ration, botb patient and practitioner will be in contact 9. Hovgaard O, Borg B. Den abrasionsmsessige effekt af en ny with the aerosol that contains oral bacteria and tandrensningsmetode. Dan Dent J 1986;90:l-6. sodium hicarhonate particles.^' Worrall et aP* found 10. Galloway SE, Pashley DH. Rate of removal of root structure by use of the Prophy-Jet device. J Periodontol 1987;58; that the level of airborne microorganisms and dust 464-469. particles were bigher during air polishing than while 11. Kontturi-Narhl V, Marklcanen S, Marklcanen H. Effects of using ruhher cup and pumice. These authors recom- airpolishing on dental plaque removal and hard tissues as mended protective eye wear, mask, gloves, and high evaluated by scanning electron microseopy. J Periodontol volume aspiration. 1990:61:334-338. Studies have shown that skin contact with the 12. Newmann PS, Silverwood RA, Dolby AE. The effects of an sodium bicarbonate aerosol can result in redness and airbrasive instrument on dental hard tissues, skin and mucosa. BrDentJ 1985; 159:9-12. itching.'^ Lubricafion of tbe pafient's lips prior to pol- 13. Barnes CM, Hayes EF, Leinfelder KF. Effects of an airabra- ishing is advisable for patient comfort and decreasing sive polishing system on restored surfaces. Gen Dent the drying effect of the sodium bicarbonate powder.^^ 1987;35:186-189. The present study indicates that the air polisher used in this study has a strong abrading effect on

410 Volume 32, Number 5, 2001 • Agger et al

14. Gutmann MSE, Marker VA, Gutmann JL. Restoration sur- 20. Melherg )R. The relative abrasivity of dentai prophylactic face roughness after air-powder poiisbing. Am J Dent pastes and abrasives on enamei and dentin. Clin Prev Dent 1993;6:99-102. 1979:6:13-18. 15. Hâkansson JP. lílinisk, histoiogisk utvardering av hehan- 21. Stooiiey GK. In vitro estimates of enamel and dentin abra- dling med Prophy-Jet. Swed Dent J !983;20:1Ü84-1090, sion associated with a prophylaxis. J Dent Res 1978:57:36. 16. Mishkin DJ, Engier WO, Javed T, Darby TD, Cobb RL, 22. Cbristensen RP, Bangerter MS. Immediate and long-term in Coffman MA. A ciinieal cotnparison of the effect on the vivo effects of polishing on enamel and denlin. J Prosthet gingiva of the Prophy-Jet and the rubber cup and paste Dent 1987:57:150-160. techniques. J Periodontoi 1986;57:151-154. 23. Gantes BG, Nivéus R, Lie T, Leknes KN. Tbe effect of 17. Kontturi-Närhi V, Markkanen S, Markkanen H. The gingi- hygiene instruments on dentin surfaces: Scanning Electron vai effects of dentai airpolishing as evaiuated by scanning Microscopic. J Periodontol 1992:63:151-157. electron microscopy. J Periodontol 1989;60:19-22. 24. Worrall SF, Iinibbs PJ, Glenwrigbt HD. Methods of reduc- 18. Efsen J, Nergaard Hansen H, Christiansen S. Laser pro- ing hacterial contamination of the atmosphere arising from filometry. In: Serup J, Jetnec GBE [eds]. Non-invasive use of an air-polisher. Br Dent J 1987:163:118-119. Methods and the Skin, Boca Raton: CRC Press, 1995- 97-106. 25. Gerbo LR, Barnes CM, Leinfelder KF. Applications of the air-powder polisher in clinical orthodontics. Am J Orthod 19. Stookey GK, Schetnehorn BR. A method for assessing the Dentofaciai ürthup 1993:103:71-73. relative abrasion of prophylaxis materiais, J Dent Res 1979:58:588-592.

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