SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

Jan Kiryk; Jacek Matys; Kinga Grzech-Leśniak; Marzena Dominiak; Małgorzata Małecka; Piotr Kuropka; Rafał J Wiglusz; Maciej Dobrzyński

doi:10.3390/ma14164469

SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

Materials (Basel). 2021 Aug 10;14(16):4469. doi: 10.3390/ma14164469.

Authors

Jan Kiryk¹, Jacek Matys², Kinga Grzech-Leśniak^{2

3}, Marzena Dominiak¹, Małgorzata Małecka⁴, Piotr Kuropka⁵, Rafał J Wiglusz⁴, Maciej Dobrzyński⁶

Affiliations

¹ Dental Surgery Department, Medical University of Wroclaw, 50-425 Wroclaw, Poland.
² Laser Laboratory at Dental Surgery Department, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland.
³ Department of Periodontics School of Dentistry, Virginia Commonwealth University, VCU, Richmond, VA 23298, USA.
⁴ Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland.
⁵ Department of Histology and Embriology, Wroclaw University of Environmental and Life Sciences, Norwida 31, 50-375 Wroclaw, Poland.
⁶ Department of Pediatric Dentistry and Preclinical Dentistry, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland.

Abstract

(1) Background: This study aimed to evaluate the microporosity of the tooth surface structure adjacent to the cemento-enamel junction (CEJ) after the removal of composite fillings with a drill in comparison with removal by an Er:YAG laser and after cleaning with a periodontal curette, chemical EDTA and NaOCl (sodium hypochlorite) conditioning. (2) Methods: The research material consisted of 30 extracted premolars with cervical composite fillings. The teeth were divided into six groups according to the method of tooth preparation: group G1 (n = 5)-a diamond drill; group G2 (n = 5)-a diamond drill + curette; group G3 (n = 5)-a diamond drill + 24% EDTA (PrefGel, Straumann, Switzerland); group G4 (n = 5)-an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) set with the following parameters: power: 1.65 W (composite removal, CR), 1.2 (tooth conditioning, TC), energy: 110 mJ (CR), 80 mJ (TC), frequency: 15 Hz, pulse duration: 50 μs, tip diameter: 1 mm, air/fluid cooling: 4, distance 1.5 mm, energy density: 14.01 J/cm² (CR), 10.19 J/cm² (TC); group G5 (n = 5)-an Er:YAG laser + 2% sodium hypochlorite (NaOCl); group G6 (n = 5)-an Er:YAG laser + 5.25% NaOCl. In each tooth, three cavities were made and subjected to analysis. The dentin surface was evaluated using a scanning electron microscope (SEM). (3) Results: Groups G1 and G2 exhibited mechanical damage to the tooth surface structure caused by the rotary motion of a diamond drill. The SEM image showed a smear layer that could only be removed chemically using 24% EDTA gel (group G3). The tooth surfaces prepared with the Er:YAG laser (groups G4-G6) revealed a homogeneous structure without damage along with open dentinal tubules (without smear layer) and visible denaturation of collagen fibers. The sodium hypochlorite (NaOCl) conditioning did not increase the visibility of dentinal tubules. (4) Conclusions: Dentin surfaces have open dentinal tubules after removal of the composite filling using the Er:YAG laser and therefore do not require additional NaOCl conditioning.

Keywords: CEJ; collagen fibers; dentinal tubules; gingival recession; smear layer.