An investigation of the effect of scaling-induced surface roughness on bacterial adhesion in common fixed dental restorative materials.
BACKGROUND
Bacterial plaque must be routinely removed from teeth, adjacent structures, and prostheses. However, the removal of this plaque can inadvertently increase the risk of future bacterial adhesion.


OBJECTIVE
The purpose of this investigation was to assess the change in the surface roughness of 3 different surfaces after dental prophylactic instrumentation and how this influenced bacterial adhesion.


METHODS
Forty specimens each of Type III gold alloy, lithium disilicate, and zirconia were fabricated in the same dimensions. The specimens were divided into 4 groups: ultrasonic scaler, stainless steel curette, prophylaxis cup, and control. Pretreatment surface roughness measurements were made with a profilometer. Surface treatments in each group were performed with a custom mechanical scaler. Posttreatment surface roughness values were measured. In turn, the specimens were inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus. Bacterial adhesion was assessed by rinsing the specimens with sterile saline to remove unattached cells. The specimens were then placed in sterile tubes with 1 mL of sterile saline. The solution was plated and quantified. Scanning electron microscopy was performed. The statistical analysis of surface roughness was completed by using repeated-measures single-factor ANOVA with a Bonferroni correction.


RESULTS
The surface roughness values for gold alloy specimens increased as a result of prophylaxis cup treatment (0.221 to 0.346 Ra) (P<.01) and stainless steel curette treatment (0.264 to 1.835 Ra) (P<.01). The results for bacterial adhesion to gold alloy proved inconclusive. A quantitative comparison indicated no statistically significant differences in pretreatment and posttreatment surface roughness values for lithium disilicate and zirconia specimens. In spite of these similarities, the overall bacterial adherence values for lithium disilicate were significantly greater than those recorded for gold alloy or zirconia (P<.05). Instrumentation of the lithium disilicate and zirconia with the stainless steel curette significantly increased bacterial adhesion compared with the control (P<.05).


CONCLUSIONS
The results of this investigation indicate that Type III gold alloy exhibited increased surface roughness values after stainless steel curette and prophylaxis cup treatments. Zirconia was less susceptible to bacterial adhesion than lithium disilicate, and greater bacterial adhesion was found for the stainless steel curette than the other instrumentation methods.
Resident, United States Air Force, Lackland Air Force Base, Joint Base San Antonio, San Antonio, Texas. Electronic address: matthew.checketts.1@us.af.mil.
Matthew R
MR
Checketts
Assistant Professor, Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
Ilser
I
Turkyilmaz
Assistant Professor, Department of Prosthodontics, Dental School, Gazi University, Ankara, Turkey.
Neset Volkan
NV
Asar
D000190:Actinomyces / Q000302:isolation & purification / Q000502:physiology; D001422:Bacterial Adhesion / Q000502:physiology*; D058491:Bacterial Load; D003475:Curettage / Q000295:instrumentation; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003777:Dental Prophylaxis / Q000295:instrumentation; D003793:Dental Restoration, Permanent; D012534:Dental Scaling / Q000295:instrumentation / Q000379:methods*; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D007779:Lactobacillus acidophilus / Q000302:isolation & purification / Q000502:physiology; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013193:Stainless Steel / Q000737:chemistry; D013295:Streptococcus mutans / Q000302:isolation & purification / Q000502:physiology; D013499:Surface Properties; D014465:Ultrasonics / Q000295:instrumentation; D015040:Zirconium / Q000737:chemistry
D003764:Dental Materials; D006047:Gold Alloys; C508050:IPS e.max Press; C493120:lithia disilicate; D003776:Dental Porcelain; D013193:Stainless Steel; D015040:Zirconium; C028541:zirconium oxide