In vitro comparison of root surface roughness and bacterial adhesion following treatment with three different instruments

The effects of anodization and instrumentation on titanium abutment surface characteristics and biofilm formation

PURPOSE

To assess the impact of anodization and instrumentation on titanium abutment surface characteristics (surface roughness and wettability) and biofilm formation (viability and mass).

MATERIALS AND METHODS

Titanium discs were obtained from pre-milled abutment blanks made of titanium-6aluminum-7niobium alloy. Polished samples were divided into three groups: un-anodized, gold-anodized, and pink-anodized. Instrumentation methods included no-instrumentation, air polishing, and titanium scaling treatment. Surface roughness was measured using an optical profilometer, and wettability was determined by measuring the contact angles using the sessile drop method with an optical tensiometer. Biofilm formation by Streptococcus sanguinis was evaluated based on the biofilm viability and mass. The biofilm viability was evaluated through colony-forming unit counting (CFU/mL), and biofilm mass was assessed with crystal violet staining (mean absorbance measured at 490 nm, in optical density values). Sample surfaces before and after biofilm formation were also examined by scanning electron microscope (SEM). Two-way ANOVA was performed to determine the group differences, and Spearman's correlation (ρ) was used to analyze the correlation among surface roughness, wettability, and CFU/mL (α = 0.05).

RESULTS

Pink anodization significantly increased surface roughness (0.38 ± 0.07 µm, p < 0.001) compared to un-anodized samples (0.25 ± 0.01 µm), while gold anodization did not (0.24 ± 0.03 µm, p = 0.301). Among pink-anodized groups, air polishing resulted in significantly lower surface roughness (0.33 ± 0.08 µm) compared to titanium scaling (0.51 ± 0.11 µm, p < 0.001) and no instrument treatment (0.38 ± 0.07 µm, p = 0.050). Anodization significantly increased wettability (p < 0.001), while instrumentation with a titanium scaling decreased it (p < 0.001). The combination of un-anodized samples and titanium scaling treatment showed the lowest wettability with the highest contact angle (70.72 ± 2.63°). The biofilm viability, measured by CFU/mL, was significantly inhibited by anodization (p < 0.001) and air polishing (p < 0.001) while promoted by titanium scaling (p < 0.001). Gold-anodized titanium discs subjected to air polishing exhibited the lowest CFU/mL (279,420 ± 16,300), while un-anodized samples instrumented with a titanium scaler had the highest CFU/mL (945,580 ± 13,580). Biofilm mass, quantified by optical density values, was significantly inhibited by anodization (p < 0.001) as well as air polishing (p = 0.001). A moderate negative correlation was observed between CFU and wettability (ρ = -0.55, p < 0.001).

CONCLUSION

Gold- and pink-anodized titanium surfaces were more hydrophilic, leading to less biofilm formation than un-anodized ones. Biofilm formation was inhibited by air polishing while promoted by titanium scaling. Gold anodization combined with air polishing had the least biofilm formation and can be considered the preferred abutment anodization/instrumentation combination.

Do instrument kinematics and the apical preparation limit influence canal disinfection and bacterial extrusion?

This in vitro research assessed the influence of the instrument kinematics (rotary and reciprocating) and the apical preparation limit on the root canal disinfection and apical bacterial extrusion. After 21 days of Enterococcus faecalis biofilm formation in 72 mesial root canals of mandibular molars, the root canals were distributed into 2 groups (n = 36) according to the systems used for preparation: ProDesign S and Reciproc. The groups were redistributed according to the limit of apical preparation (n = 11): (a) 1 mm up to the apical foramen (TL-1); (b) at the apical foramen (TL = 0); (c) 1 mm beyond the apical foramen (TL + 1). After preparation, the remaining biofilm adhered to the dentin walls at the apical third was removed by sonication. The aliquots of bacterial suspension released, and the irrigating solution leaked through the apical foramen during preparation were plated for colony-forming units (CFUs) counting. Data were statistically assessed by the Kruskal-Wallis and Dunn tests (α = 5%). Both systems promoted decontamination of the apical third, regardless the limit of apical preparation (p > 0.05). A larger quantity of bacteria was extruded from the root canals prepared 1 mm beyond the apical foramen, regardless the instrumentation kinematics (p < 0.05). The apical third of the root canal was efficiently decontaminated after preparation, regardless the instrumentation kinematics and the apical limit. However, a larger quantity of bacterial extrusion was observed when preparation was performed beyond the anatomical root canal limits.

Micro-CT evaluation of the effect of various ScRp instrumentation methods on cement loss, porosity and micro-crack formation

OBJECTIVES

The purpose of this study was to compare the effectiveness of three different instruments on cement loss, porosity and micro-crack formation, which was not evaluated before, following scaling and root planning (SRP) using micro-computed tomography (micro-CT).

METHODS

In this experimental study, 30 single-rooted extracted human teeth were used and divided into three groups. All the teeth were scanned with micro-CT before and after SRP. Group 1: SRP was performed with Gracey curettes, Group 2: SRP was performed by using an ultrasonic device, and Group 3: SRP was performed by using diamond burs. Cement loss from the root surface, porosity, and micro-crack formation in the root dentine were analysed. Micro-CT is used for qualitative and quantitative analysis of samples. The obtained data were analysed statistically (p < 0.05).

RESULTS

Minimum cement loss following SRP was detected with ultrasonic scaler (26.98 mm3), whereas the highest was created by diamond burs (96.20 mm3) (p < 0.05). The total porosity values after SRP were 0.278%, 0.334% and 0.252% for Groups 1, 2 and 3, respectively. Although Group 3 had the least porosity values, there was no statistically significant difference between the groups. The highest micro-crack formation was seen in Group 2 and the lowest was in Group 1 with a significant difference (p < 0.05).

CONCLUSIONS

More cement loss was observed with diamond burs. Ultrasonic devices appear to be a viable alternative to instrumentation with curettes. However, ultrasonic devices should be used carefully because of micro-crack formation since the micro-crack resulting from instrumentation with hand instruments is the least of all.

Effects of a new magnetostrictive ultrasonic scaler and a traditional piezoelectric ultrasonic scaler on root surfaces and patient complaints

Tooth wear and pain are the primary concerns of patients undergoing periodontal scaling. The aims of this study were to compare the effects of a new magnetostrictive ultrasonic scaler and a traditional piezoelectric ultrasonic scaler on tooth surface roughness and calculus removal and to determine their impacts on patient discomfort during supragingival cleaning. This article had two parts: an in vitro study and a clinical study. In the in vitro study, thirty teeth with subgingival calculus were randomly assigned to two scaling treatment groups: magnetostrictive scalers (n = 15) and piezoelectric scalers (n = 15). Surface roughness measurements were taken at baseline and after scaling, and the root samples were visualised by SEM after scaling. Additionally, a single-centre randomised split-mouth clinical trial was conducted. Eighty-five participants diagnosed with chronic gingivitis or periodontitis were randomly assigned to receive supragingival scaling. The magnetostrictive scaler was used in half of the mouths (n = 85), and the piezoelectric scaler was used in the other half of the mouths (n = 85). Data on pain, noise, and vibration were collected using a VAS questionnaire, and the operating time was recorded. In both in vitro and clinical studies, magnetostrictive scalers were reported to be more effective than piezoelectric scalers in removing dental deposits (P < 0.05). Additionally, the root surface after scaling with the magnetostrictive scaler was smoother than that after scaling with the piezoelectric scaler in the in vitro study (P = 0.02). SEM examination also revealed that fewer dental materials were lost after instrumentation with the magnetostrictive scaler than after instrumentation with the piezoelectric scaler. Piezoelectric scalers caused less discomfort to patients in terms of pain, noise, and vibration than magnetostrictive scalers (P < 0.05). According to this clinical study, the magnetostrictive scaler caused more discomfort during supragingival scaling than the piezoelectric scaler. Moreover, the magnetostrictive scaler was also more efficient and produced a smoother root surface with less material loss after scaling than the piezoelectric scaler, as demonstrated in the in vitro study.