Erbium Chromium Laser in Pulp Capping Treatment

Erbium Chromium Laser in Pulp Capping Treatment Dr. Giovanni Olivi a, Dr. Maria Daniela Genovese a a Private Practice, Rome, Italy Purpose: Direct pulp capping represents the borderline between restorative and endodontic dentistry. The aim of this investigation was to asses the effectiveness of an Er,Cr:YSGG laser (2780 nm, Waterlase, Biolase) combined with the use of calcium hydroxide cement base in direct pulp capping. Materials and Methods: A total of 25 carious cavities in 25 patients were selected for investigation and treatment. The total number was split into two treatment groups, dependant upon the clinical condition. Group A: 13 teeth; these cavities did not display exposure of the pulp. Group B: 12 teeth; these cavities displayed a vital exposure of the pulp. Both groups underwent cavity preparation to remove caries and define restorative form. After cavity preparation, group A was treated with the laser using the following parameters: a 600-μm tip at 1 W, 20 pps for 60 s (water 55%, air 65%) in focused mode for disinfection, and at 1 W, 20 pps for 30 s (water 15%, air 25%) in defocused mode to perform dentin melting. Group B was treated with the same parameters as above, followed a defocused irradiation at 0.5 W, 20 pps for 10 s, with no water and 45% air, to coagulate the pulp. In all cases, the treated area was protected a base of calcium hydroxide prior to being restored with a totaletch bonding system and a flowable microhybrid composite. Results: All cases treated with the Er,Cr:YSGG laser proved positive clinical pulp vitality after 6 months. At the 48-month follow-up, group A revealed two teeth with negative vitality (equal to 84.6% success), and in group B, another two teeth with negative pulp vitality (83.3% success) were found. Conclusions: The Er,Cr:YSGG laser appears to be effective as an adjunct in pulp capping procedures. To obtain more conclusive and statistically significant results, it may be necessary to repeat the treatment regime, using a larger sample. Keywords: erbium:yag laser, Er,Cr:YSGG laser, pulp capping, calcium hydroxide. J Oral Laser Applications 2006; 6: 291-299. Submitted for publication: 04.05.06; accepted for publlication: 06.10.06. Pulp capping, as an elective procedure, can be viewed as representing a borderline between restorative and endodontic dentistry. Where possible, the maintenance of pulp vitality greatly improves the dental prognosis, from both a biomechanical and esthetic point of view. Research into new techniques and technologies in order to enhance success can therefore be justified. A review of published literature reveals that the high success rates reported refer to pulp capping on fractured anterior teeth 1,2 with an important correlation with age, while molars 3,4 treated for deep decay present much lower success rates. The most recent studies report long-term success rates close to 90% for laser-assisted pulp capping, compared to a success rate of about 60% with traditional methods. In 1997, Santucci 5 recorded a success rate of 90% after 54 months using a Nd:YAG laser, compared to the control group. Moritz 6,7 conducted two studies using a pulsed CO 2 laser and reported success rates of 93% and 89% respectively, compared to the control group which used traditional methods and calcium hy- Vol 6, No 4, 2006 291

Fig 1 Slight pulp exposure after preparation of a deep carious cavity (exposure up to 1 to 1.5 mm). Moderate bleeding suggests a treatment of pulp capping, especially in young patients. Fig 2 The site of pulp exposure is important for the regenerative capacity and for the healing of the pulp: a coronal site has a better prognosis than a cervical site. droxide. Studies performed Jayawardena 8 with an erbium laser demonstrated good healing capacity with the formation of a dentin bridge and repaired dentin. Cohen and Burns 9 have defined the treatment as follows: pulp capping is the application of a medicament or dressing to the exposed pulp in an attempt to preserve vitality. In addition, Ingle 10 stated: direct pulp capping is the protection of a pulp exposed through trauma to the anterior teeth, accidental mechanical exposure during tooth or cavity preparation or deep dentinal decay. Indications A successful outcome of restorative treatment, inclusive of necessary pulp capping, partial pulpotomy, and cervical pulpotomy, is dependent on following protocols based on the presenting criteria. Such criteria include: the recent dental history in the case of deep cavities (without symptoms or with mild sensitivity to heat stimulation) the time between trauma and treatment (24 to 48 h) the patient s age the maturity of the tooth the condition of the pulp tissue (active hyperemia and/or reversible pulpitis) and the amount of bleeding (indicative of irreversible pulp change) the dimensions and the location of exposure (0.5 to 1.5 mm, coronal site) (Figs 1 and 2) the radiographic absence of periapical lesions the type of restoration chosen (pulp capping procedures should not be undertaken on prospective fixed-bridge abutments). Contraindications Where radiographic examination reveals thickening of the apical periodontal ligament, or there is excessive dental mobility, heavy bleeding, or the excretion of pus from the pulp cavity, a pulp capping procedure is not indicated. Diagnosis Diagnostic examination to assist in treatment planning includes: thermal and electric tests objective exam (the absence of mobility and pain upon percussion) radiographic examination. Pulp Capping Agent Traditional techniques make use of calcium hydroxide, the properties of which are already well known (Table 1). Recently, the use of mineral trioxide aggregate 292 The Journal of Oral Laser Applications

Table 1 Comparison of pulp capping agents Calcium hydroxide Mineral trioxide aggregate (MTA) Biocompatible Biocompatible Fairly good seal Good seal Soluble Insoluble Promotes dentinal bridge Promotes dentinal bridge Bacteriostatic action Bacteriostatic action ph 10.5-12.5 ph 12.5 Needs dry field Needs wet field Easy to remove Difficult to remove Economical Expensive Doesn t change tooth color Can stain the tooth Predictable and tested Long-lasting action (?) Table 2 Description of teeth treated Group A 11 posterior teeth without macroscopically evident pulp exposure Group A 2 anterior teeth without macroscopically evident pulp exposure Group B 9 posterior teeth with pulp exposure 0.5 > 1.5 mm Group B 3 anterior teeth with pulp exposure 0.5 >1.5 mm (MTA) 11 has been introduced; its ph and biocompatibility are similar to calcium hydroxide, but its greater sealing capacity and duration in situ prolong its necrotizing action on the pulp, allowing the formation of a more apical dentinal bridge. Reduced ease of manipulation, higher cost, and the necessity of performing the restoration at a later appointment tends to restrict the use of MTA to treating root perforations or apical fillings in endodontic surgery. 12 The purpose of this study was to evaluate the efficacy of the physical action of the Er,Cr:YSGG laser combined with a base of calcium hydroxide to improve the clinical outcome of pulp capping procedures. MATERIALS AND METHODS Table 3 Patient age and number Group A 15 25 years 6 Group A 26 40 years 7 Group B 15 25 years 6 Group B 26 40 years 5 Group B > 40 years 1 In this study an Er,Cr:YSGG laser (2780 nm, Waterlase YSGG, BioLase Technology; San Clemente, CA, USA) was used. In all teeth treated, a G6 sapphire handpiece tip (600 μm) was used, combined with a base of calcium hydroxide. The patients treated for the pulp capping procedure were selected according to the indications given above. A total of 25 carious teeth (20 posterior and 5 anterior teeth) were divided into 2 groups and treated with pulp capping. Group A comprised 13 teeth without macroscopically evident pulp exposure, and group B comprised 12 teeth with pulp exposure (0.5 > 1.5 mm) (Table 2). The age of the 25 patients ranged from 15 to 40 years, with one patient aged 56 years (Table 3). After completing the cavity preparation with the laser, cases without pulp exposure (group A) were treated with the laser at 1 W, 20 pps, 50 mj, for 60 s (water 55%, air 65%) in focused mode (1.5 mm) to achieve a bactericidal effect, and at 1 W, 20 pps, 50 mj, for 30 s (water 15%, air 25%) in defocused mode to perform dentin melting (Fig 3). Vol 6, No 4, 2006 293

Fig 3 Carious cavity close to the pulp (tooth 23). Sealing of dentinal tubules melting with Er,Cr:YSGG laser (1.0 W, 20 pps, 25% air, 15% water in defocused mode). Fig 4 Pulp exposure (tooth 24) with absence of bleeding. Superficial coagulation performed with Er,Cr:YSGG laser (0.5 W, 20 pps, 45% air cooling, no water) in defocused mode. system (Scotchbond Mult-Purpose, 3M; St. Paul, MN, USA) to obtain dentin sealing (Fig 5), and a microhybrid composite (Enamel Plus, GDF; Rosbach, Germany). RESULTS Fig 5 After laser decontamination, coagulation or melting of the cavity, a liner of calcium hydroxide is applied. It is important to obtain immediate and hermetic sealing of the prepared cavity to avoid recontamination. Cases with pulp exposure (group B) were treated with the same parameters as above for cavity preparation and disinfection, followed a defocused irradiation at 0.5 W, 20 pps, 25 mj, for 10 s with no water and 45% air on the exposed pulp to perform soft tissue coagulation (Fig 4). After laser irradiation, the treated area was protected with a base of pure calcium hydroxide in group A, or with self-curing calcium hydroxide in group B. In all cases, restoration was completed with an adhesive No significant difference was found between groups A and B. Two out of 12 treated cases with direct pulp capping failed after 12 months; 2 out of 13 treated cases without pulp exposure failed after 48 months, with a total success rate of 84% (Table 4). A difference was found between anterior and posterior teeth: all 5 anterior teeth (100%) treated with the Er,Cr:YSGG laser maintained their vitality after 48 months; 16 of the 20 posterior teeth (80%) treated maintained vitality after 48 months. No difference was found based on the age of the patient. The outcome was judged successful if pain was absent, periaprical lesions in the roots were absent, and there was evidence of the formation of a dentinal bridge (clinical history, pulp vitality test, radiographic exams). DISCUSSION The use of the Er,Cr:YSGG laser allows cavity preparation to be completed with only one instrument, in contrast to the alternate use of high- and low-speed rotary instruments and other laser wavelengths (CO 2, Nd: 294 The Journal of Oral Laser Applications

Table 4 Clinical results (failure/success) Total 84% survival after 48 months (4/25) Posterior teeth 80% survival after 48 months (4/20) Anterior teeth 100% survival after 48 months (0/5) Group A 84,6% survival after 48 months (2/13) Group B 83,3% survival after 48 months (2/12) YAG, and diode lasers), which cannot be used for ablation of hard tissue. When using the Er,Cr:YSGG laser in pulp capping to create the biological base for the formation of a sterile area, the creation of a dentinal bridge, and for the maintenance of pulp vitality, the following may be considered as contributing effects: 1. The sterile area is due to the bactericidal effect of the laser, an effect common to all wavelengths. There are many studies that have demonstrated the bactericidal power of lasers 13,14 but it is important to emphasize the different action of different lasers and the different depths of penetration in the target tissue. The CO 2 and the erbium group of lasers are more superficial in their interaction with tissue than the diode and Nd:YAG wavelengths, which penetrate more deeply (up to 500 to 1000 μm) 15 and have a greater capacity for scattering (Fig 6). The decontaminating action of the laser, more or less superficial, must be completed with immediate sealing of the exposed pulp area to avoid recontamination through leakage. 2. The coagulating effect of the laser guarantees a dry operating area, with no bleeding and the creation of a zone of necrosis that is more superficial compared to a chemical pulp capping agent 12 (Fig 7). Significantly, different lasers have different hemostatic or coagulating effects due to the differences in absorption the target tissue (pigment, water, or dentin) (Figs 8 to 10). 3. Only the use of the erbium laser (2780 to 2940 nm) limits a pressure increase in the dental cavity, thus avoiding the risk of pushing either mechanically or manually the infected dental chips into the pulp tissue during caries removal. 9 4. The use of the erbium laser, compared to lasers with other wavelengths and compared to traditional mechanical rotating instruments, limits temperature increase in the pulp chamber and may even produce a decrease. 16,17 Fig 6 Different laser/tissue interaction of near, medium and far infrared wavelength. Erbium and CO 2 laser have a superficial interaction with target tissue. Diode and Nd:YAG laser have a body interaction with the target tissue, resulting in deeper penetration and a high capacity for scattering. 5. In the case of a near-exposure of pulpal tissue but without macroscopically evident exposure, a soft, gentle irradiation of this limited area with a moderate, controlled thermal effect allows the formation of a barrier against bacterial contamination and chemical/mechanical stimuli of the pulp tissue. With SEM examination, the obliteration of the dentinal tubules, creating a limited area of melting that protects the underlying pulp, can be observed (Fig 11) (Olivi G, 12th ALD Conference, New Orleans, LA, USA, April 6-8, 2005). The use of the erbium laser is also important for its selective ablation of caries, minimally invasive preparation, and the possibility of reducing the use of local anesthesia (Figs 12 to 18). Vol 6, No 4, 2006 295

Fig 7a Graphic representation of laser-assisted pulp capping and of formation of dentinal bridge. Fig 7b Laser/tissue interaction. Fig 7c Laser/tissue interaction. N: necrosis area 80 C; C: coagulation area 60 C; W: warming area of reversible damage 35 to 50 C, stasis of capillaries and migration of leukocytes. Fig 7d Application of a base of calcium hydroxide (CH), immediate filling with flowable composite (F) and microhybrid composite (C); the fibroblasts migrate in the zone under calcium hydroxide, where the dentinal bridge will form. Fig 7e After some weeks calcification begins. Fig 7f Odontoblasts (O) in the dentinal bridge zone: almost calcified dentin and almost normal pulp. 296 The Journal of Oral Laser Applications

Fig 8 Pulp exposure (tooth 16) with moderate bleeding. Coagulation performed with diode 810-nm laser (0.8 W, cw in defocused mode). Fig 9 Pulp exposure (tooth 23) with absence of bleeding. Coagulation performed with Er:YAG laser (0.21 W, 3 pps, 70 mj, no water-air cooling) in defocused mode. Fig 10 Intra-operative view. Microscope image 40X (tooth 16): area of dentin vitrification performed with Er,Cr:YSGG laser. Fig 11 SEM image (2200X) of melting with partial closure of dentinal tubules performed with Er,Cr:YSGG laser. In vitro sample control. Fig 12 Clinical case: occlusal decay of teeth 26, 27 in 20-year-old male patient. Fig 13 Pre-operative radiograph, showing a deep cavity on tooth 27. Vol 6, No 4, 2006 297

Fig 14 Cavity preparation performed with Er,Cr:YSGG laser. Fig 15 (left) After the cavity finishing and checking, a small pulp exposure on tooth 27 appeared. (right) Laser coagulation and capping with self-curing calcium hydroxide. Fig 16 (left) Enamel acid etching (37% orthophosphoric acid for 15 s). (right) Enamel and dentin total-etching (37% orthophosphoric acid for 15 s). Fig 17 Composite resin restoration. Fig 18 One-year postoperative radiograph. 298 The Journal of Oral Laser Applications

CONCLUSION Laser use in restorative dentistry not only allows an improvement in patient approach (no contact, no vibration, reduced need of anesthesia), but also improves the prognosis in treatments such as pulp capping, where maintaining dental vitality is a determining factor in clinical success. For their bactericidal and coagulating effect, all wavelengths, even with different effects and usage, can be used effectively in this procedure. In our experience, the use of the Er,Cr:YSGG laser (2780 nm) allows us to combine the advantages of laser preparation of the tooth with the treatment of pulp exposure. ACKNOWLEDGMENTS The SEM image resulted from the collaboration with University of Siena (Italy), Institute of Anatomy (Director Prof. L. Fonzi). We want to thank both Prof. L. Fonzi and Prof. V. Kaitsas for allowing this image to be published. REFERENCES 1. Cvek M. A clinical report on partial pulpotomy and capping with calcium hydroxide in permanent incisors with complicated crown fracture. Endod 1978;4:232-237. 2. Haskell EW, Stanley HR, Chellemi J, Stringfellow H. Direct pulp capping treatment:a long-term follow-up. J Am Dent Assoc 1978;97:607-612. 3. Clement AW, Willemsen WL, Bronkhorst EM. Success of direct pulp capping after caries excavations. Ned Tijdschr Tandheelkd 2000;107:230-232. 4. Aushill TM, Arweiler NB, Hellwig E, Zamani-Alaei A, Sculean A. Success rate of direct pulp capping with calcium hydroxide. Schweiz Monatsschr Zahnmed 2003;113:946-952. 5. Santucci PJ. Dycal versus Nd:YAG laser and Vitrebond for direct pulp capping in permanent teeth.j Clin Laser Med Surg 1999;17: 69-75. 6. Moritz A, Schoop U, Goharkhay K, Sperr W. Advantages of a pulsed CO2 laser in direct pulp capping: long term in vivo study. Laser Surg Med 1998;22:288-293. 7. Moritz A, Schoop U, Goharkhay K, Sperr W. The CO 2 laser as an aid in direct pulp capping. J Endod 1998;24:248-251. 8. Jayawardena JA, Kato J, Moriya K, Takagi Y. Pulpal response to exposure with Er:YAG laser. Oral Surg Oral Med Oral Pathos Oral Radiol Endod 2001;91:222-229. 9. Cohen S, Burns RC. Pathways of the pulp, ed 3. St. Louis:Mos, 1984:501-506, 756-766. 10. Ingle JI. Endodontics, ed 3. Philadelphia: Lea &Febiger, 1985:782-809. 11. Koh ET, McDonald F, Pitt Ford TR, Torabinejad M. Cellular response to Mineral Trioxide Aggregate. J Endod 1998;24:543-547. 12. Riccitiello F, D Ambrosio C, Simeone M, Rengo S. Pulpotomia: indicazioni,diagnosi,terapia. Dentista Moderno 2005;Feb:23-47. 13. Moritz A, Schoop U, Goharkhay K, Jakolitsch S, Kluger W, Wernisch J, Sperr W. The bactericidal effect of Nd:YAG, Ho:YAG, and Er:YAG laser irradiation in the root canal: an in vitro comparison. J Clin Laser Med Surg 1999;17:161-164. 14. Schoop U, Kluger W, Moritz A, Nedjelik N, Georgopulos A, Sperr W. Bactericidal effect of different laser systems in deep layers of dentin. Laser Surg Med 2004;35:111-116. 15. Gutknecht N, Moritz A, Conrads G, Sievert T, Lambert F. Bactericidal effect of the Nd:YAG laser in in vitro root canals. J Clin Laser Med Surg 1996;14:77-80. 16. Rizoiu I, Kohanghadosh F, Kimmel AI, Eversole LR. Pulpal thermal responses to an erbium,chromium:ysgg pulsed hydrokinetic system. Oral Surg Oral Med Pathos Oral Radiol Endod 1998;86: 220-223. 17. Glockner K, Rumpler J, Ebeleseder K, Stadtler P. Intrapulpal temperature during preparation with the Er:YAG laser compared to the conventional burr: an in vitro study. J Clin Laser Med Surg 1998;16:153-157. Contact Dr. Giovanni Olivi, 00152 Piazza F. Cucchi, 3 Rome, Italy. Tel/Fax: +39-06-581-5190. e-mail: olivi.g@tiscali.it Vol 6, No 4, 2006 299