Effect of implant type on the stability of cantilever fixed dental prostheses: An in vitro study.

OBJECTIVES: To simulate the replacement of a premolar with an implant-supported cantilever fixed dental prosthesis (ICFDP) and how the fracture load is affected by implant type, positioning within the zirconia blank, and aging protocol. MATERIALS AND METHODS: Seventy-two ICFDPs were designed either within the enamel- or dentin layer of a 4Y-PSZ blank for bone-level and tissue-level titanium-zirconium implants. Fracture load was obtained on the cantilever at baseline (no aging) or after aging in a chewing simulator with the load applied within the implant axis (axial aging) or on the cantilever (12 groups with n = 6). A three-way ANOVA was applied (α = .05). RESULTS: A three-way ANOVA revealed a significant effect on fracture load values of implant type (p = .006) and aging (p < .001) but not for the position within the zirconia blank (p = .847). Fracture load values significantly increased from baseline bone level (608 ± 118 N) and tissue level (880 ± 293 N) when the implants were aged axially, with higher values for tissue level (1065 ± 182 N) than bone level (797 ± 113 N) (p < .001). However, when the force was applied to the cantilever, fracture load values decreased significantly for tissue-level (493 ± 70 N), while values for bone-level implants remained stable (690 ± 135 N). CONCLUSIONS: For ICFDPs, the use of bone-level implants is reasonable as catastrophic failures are likely to be restricted to the restoration, whereas with tissue-level implants, the transmucosal portion of the implant is susceptible to deformation, making repair more difficult.

Exploring the staining potential of 1 GSK-3 inhibitors in bovine teeth: 2 a one-year laboratory investigation.

GSK-3 inhibitors, such as Tideglusib (TG) and CHIR-99021 (CHIR), show promise in stimulating reparative dentin formation. The aim of this study was to assess the discoloration potential of TG and CHIR in an established in vitro model. Enamel-dentin specimens made from bovine incisors were randomly allocated to five groups (n=15 each): group bovine blood (BB), group dimethyl sulfoxide (DMSO), group TG, group CHIR, and group mineral trioxide aggregate (MTA). Each specimen had a central cavity in which the respective material was applied and sealed with resin-based luting material. Color determination was conducted using a dental spectrophotometer at t0 (before filling), t1 (immediately after filling), t2 (after one week), t3 (after one month), t4 (after three months), t5 (after six months), and t6 (after one year). Statistical analysis involved descriptive statistics, Kruskal-Wallis tests, and analysis of variance (α=0.05). Group BB and group CHIR exhibited the most significant decrease in lightness (ΔL*) after one year (ΔL*-4.7 and ΔL* -5.7, respectively), whereas groups DMSO, TG, and MTA showed minimal changes (DMSO ΔL*: -0.3; TG ΔL*: 1.4; MTA ΔL*: -0.5). Group BB and CHIR exhibited the highest ΔE values (6.4Å}0.6 and 6.5Å}0.8, respectively). Unlike CHIR, TG did not result in discoloration exceeding the threshold of visual perception, defined by a ΔE value of 5.5, during the one-year observation period. This laboratory study therefore suggests that TG could be utilized for indirect or direct pulp capping without major discoloration concerns. However, additional research is required to corroborate these findings.

Biofilm formation on metal alloys and coatings, zirconia, and hydroxyapatite as implant materials in vivo.

OBJECTIVES: Composition of implant material and its surface structure is decisive for oral biofilm accumulation. This study investigated biofilm formation on eight different materials. MATERIALS AND METHODS: Eighteen healthy subjects wore intraoral splints fitted with two sets of eight materials for 24 h: zirconia [ZrO2 ]; silver-gold-palladium [AgAuPd]; titanium zirconium [TiZr]; Pagalinor [PA]; hydroxyapatite [HA]; silver-platinum [AgPt]; titanium aluminum niobium [TAN]; titanium grade4 [TiGr4]. Total biomass was stained by safranin to assess plaque accumulation while conventional culturing (CFU) was conducted to investigate viable parts of the biofilm. Cell viability of human gingival fibroblasts (HGF-1) was assessed in vitro. Statistical evaluation was performed with linear mixed-effects models to compare materials (geometric mean ratios, 95% CI), with the level of significance set at ɑ = .05. RESULTS: Less biofilm mass and CFU were found on noble metal alloys (AgPt, AgAuPd, and PA). Compared to AgPt, PA had 2.7-times higher biofilm mass value, AgAuPd was 3.9-times, TiGr4 was 4.1-times, TiZr was 5.9-times, TAN was 7.7-times, HA was 7.8-times, and ZrO2 was 9.1-times higher (each p < .001). Similarly, CFU data were significantly lower on AgPt, AgAuPd had 4.1-times higher CFU values, PA was 8.9-times, TiGr4 was 11.2-times, HA was 12.5-times, TiZr was 13.3-times, TAN was 16.9-times, and ZrO2 was 18.5-times higher (each p < .001). HGF-1 viability varied between 47 ± 24.5% (HA) and 94.4 ± 24.6% (PA). CONCLUSION: Noble alloys are considered as beneficial materials for the transmucosal part of oral implants, as less biofilm mass, lower bacterial counts, and greater cell viability were detected than on titanium- or zirconia-based materials.

Stability of Cantilever Fixed Dental Prostheses on Zirconia Implants.

BACKGROUND: The objective was to determine the optimal connector size and position within zirconia disks for implant-supported cantilever fixed dental prostheses (ICFDP). METHODS: Two-unit ICFDPs (n = 60) were designed for the premolar region with connector sizes of either 9 or 12 mm2 and positioned in the enamel or dentin layer of two different types of zirconia disks. The restorations were milled and cemented onto zirconia implants. After simulated chewing for 1.2 Mio cycles, the fracture load was measured and fractures were analyzed. RESULTS: No fractures of ICFDPs or along the implants were detected after simulated aging. The mean fracture load values were significantly higher for a connector size of 9 mm2 (951 N) compared with 12 mm2 (638 N). For the zirconia material with a higher biaxial flexural strength, the fracture load values were increased from 751 to 838 N, but more implant fractures occurred. The position within the zirconia disk did not influence the fracture load. CONCLUSIONS: A connector size of 9 mm2 and a zirconia material with a lower strength should be considered when designing ICFDPS on zirconia implants to reduce the risk of fractures along the intraosseous implant portion.

Partial pulpotomy without age restriction: a retrospective assessment of permanent teeth with carious pulp exposure.

OBJECTIVES: This study aimed to retrospectively evaluate clinical and radiographic outcomes of partial pulpotomy performed in permanent teeth with carious pulp exposure. MATERIALS AND METHODS: Records of patients undergoing treatment at an undergraduate dental clinic between 2010 and 2019 were screened for partial pulpotomies in teeth with a presumptive diagnosis of normal pulp or reversible pulpitis. The follow-up had to be ≥ 1 year. Patient data were retrieved and analyzed using Mantel-Cox chi square tests and Kaplan-Meier statistics. The level of significance was set at α = 0.05. RESULTS: Partial pulpotomy was performed in 111 cases, of which 64 (58%) fulfilled the eligibility criteria. At the time of partial pulpotomy, the mean age was 37.3 (± 13.5) years (age range 18-85). The mean observation period was 3.1 (± 2.0) years. Two early failures (3.1%) and five late failures (7.7%) were recorded. The overall success rate of maintaining pulp vitality was 89.1%, with 98.4% tooth survival. The cumulative pulp survival rates of partial pulpotomy in patients aged < 30 years, between 30 and 40 years, and > 40 years were 100%, 75.5%, and 90.5%, respectively, with no significant difference between the age groups (p = 0.225). At follow-up, narrowing of the pulp canal space and tooth discoloration were observed in 10.9% and 3.1% of cases, respectively. CONCLUSIONS: Across age groups, partial pulpotomy achieved favorable short and medium-term outcomes in teeth with carious pulp exposure. CLINICAL RELEVANCE: Adequate case selection provided, partial pulpotomy is a viable operative approach to treat permanent teeth with deep carious lesions irrespective of patients' age.

Potential of intraoral optical scanning to evaluate motor skills' improvement for tooth preparation: A prospective cohort study.

INTRODUCTION: This prospective cohort study investigated the potential of digital assessment using intraoral scanning (IOS) combined with software analysis (prepCheck) to evaluate the outcome of repetitive tooth preparation and its influence on the acquisition of motor skills in dental students. MATERIALS AND METHODS: Twenty-six students completed 177 full-crown preparations of the same tooth in six practice sessions followed by a final examination. Preparations were assessed digitally using prepCheck and conventionally by calibrated faculty instructors. In addition, students assessed their own performance and this was compared with the instructors' assessments. RESULTS: Conventional assessment showed that students preparations improved over time, with 43.5% of students receiving score 2 (highest grade) at the fifth practice session. With the prepCheck assessment, statistically significant improvements indicated by an enlarged area within the tolerance range set at 0.2 mm were found between the first and the second practice session (7.5% improvement; 95% CI: 2.2%, 12.7%, p = 0.006), and between the first run and the final exam preparation (6.7%; 95% CI: 1.7%, 12.5%, p = 0.011). Agreement between instructor/student assessments was best immediately after students received visual feedback using prepCheck (76% agreement; Spearman's rho 0.78). CONCLUSION: These data indicate that IOS technology was useful for student's self-evaluation by visual feedback.

Clinical outcome of metal- and all-ceramic resin-bonded fixed dental prostheses.

PURPOSE: The aim of this retrospective cohort study was to investigate the long-term outcome of metal- and all-ceramic resin-bonded fixed dental prosthesis (RBFDP) up to 17 years, and to evaluate potential factors influencing the risk for complications. METHODS: Patients who were treated with RBFDP to replace teeth in the anterior or first premolar region in an university setting were identified from electronic records. Data collection comprised dental and periodontal parameters, periapical radiographs, and assessment of the RBFDP. Patient-reported satisfaction was evaluated on visual analog scales (VAS), and 5-year cumulative survival and success rates were calculated. Cox regression models were used to compare metal- versus all-ceramic RBFDPs. RESULTS: Seventy-one patients with RBFDP replacing 65 anterior teeth and 6 premolars were included with a mean observation period of 56.1 (±42.7) months. RBFDP cumulative survival rate was 86.7% and cumulative success rate 71.7% after 5 years, with no significant difference between metal-and all-ceramic RBFDPs. The risk for RBFDP failure was significantly higher with more than one pontic (OR 6.1; p=0.033), or negative pulp vitality testing of abutments (OR 7.3; p=0.042), while complications tended to be increased with two-wings compared to one-wing RBFDP (OR 5.4; p=0.054). CONCLUSIONS: Metal- and all-ceramic RBFDPs facilitated good long-term results, particularly with one-wing, one-cantilever, and vital abutment teeth.

Spectrophotometric insights: calcium hydroxide influences tooth discolorations induced by short-term application of antibiotic/corticosteroid pastes.

OBJECTIVES: This in vitro study aimed to assess the influence of a calcium hydroxide dressing regarding the relative color change (ΔE) of enamel-dentin specimens previously exposed to antibiotic/corticosteroid pastes. MATERIALS AND METHODS: Eighty bovine enamel-dentin specimens with a cylindrical central cavity were randomly allocated to four groups: NEG (empty), POS (blood), LED (Ledermix), and ODO (Odontopaste) (n = 20 each). The materials were applied and sealed with self-adhesive resin luting material. After 3 weeks, the materials were removed and a calcium hydroxide (Ca(OH)2) dressing was placed in all cavities. After a further 3-week storage period, the cavities were restored with resin-based composite. Spectrophotometric color measurements were taken over 6 months, and ΔE values were calculated. A Tukey's multiple comparison test was performed to assess significant differences within the treatment groups (p < 0.05). RESULTS: Tooth discolorations were present after 3 weeks in LED (ΔE 29.14 ± 6.55) and POS (ΔE 18.05 ± 7.03); NEG and ODO remained color stable (ΔE 3.2 ± 1.36 and ΔE 2.3 ± 1.16). The 3-week Ca(OH)2 dressing decreased discolorations of POS (ΔE 15.93 ± 6.63; p = 0.37), whereas LED showed a further significant increase (ΔE 39.55; p < 0.0001). Between the end of the Ca(OH)2 dressing and the final restoration no significant color changes were observed in any group (p > 0.9). CONCLUSIONS: Discolorations induced by LED progressed during the Ca(OH)2 dressing despite careful removal of all residues. CLINICAL RELEVANCE: Calcium hydroxide might negatively affect the discoloring potential of Ledermix. This highlights the need for direct intracanal application methods of Ledermix ensuring a material-free access cavity or alternative antibiotic/corticosteroid pastes such as Odontopaste should be used.

Biofilm formation on metal alloys, zirconia and polyetherketoneketone as implant materials in vivo.

OBJECTIVES: This study investigated biofilm formation on discs of metal alloys, zirconia and polyetherketoneketone in vivo. MATERIAL AND METHODS: Sixteen healthy volunteers conducted two runs of 24 hr each wearing an intraoral splint with 15 discs representing five different materials (gold-based [EL] and silver-based [PA] noble metal alloys; zirconia [ZR]; polyetherketoneketone [PEKK]; titanium zirconium alloy [TiZr]). Safranin staining assays and colony-forming unit (CFU) counts were conducted. Linear mixed-effects models were used to compare materials, and geometric mean ratios with 95% confidence interval were calculated with the level of significance set at α = 0.05. RESULTS: Less biofilm mass and lower CFU counts were found on PA and EL, while ZR and PEKK developed similar levels as the reference material TiZr alloy. Compared with PA, biofilm mass was 1.5 times higher for EL (p = .004), 1.7 times higher for PEKK (p < .001), 2.2 times higher for TiZr (p < .001) and 2.4 times higher for ZR (p < .001). The culturing method confirmed these results for EL and PA with lower CFU compared to TiZr. The biomass staining technique and cell culturing correlated for EL and PA. CONCLUSION: Silver-based noble alloy and gold-based high noble alloy demonstrated the least biofilm formation indicating a potential clinical use as material for implant components in the transmucosal compartment. Zirconia and Polyetherketoneketone revealed similar results as the reference material titanium zirconium alloy used in commercially available titanium dental implant.

Endodontic Treatment in Switzerland. A National Survey

The purpose of this study was to collect information about current treatment protocols of endodontic procedures among general practitioners (GP), endodontically interested practitioners (EI) and endodontic specialists (ES) in Switzerland and to compare them with available endodontic quality guidelines and former surveys. A questionnaire was distributed to 1,522 attendees of two national conferences (Swiss Dental Association, 2015; Swiss Society for Endodontology, 2016) addressing socio-demographic characteristics and specific questions about root canal treatments (RCT) including techniques and materials used. Five hundred and six surveys were collected comprising data of 81.8% GP, 14.4% EI and 3.8% ES (response rate: 33.2%). The majority of respondents was male (59.9%), 40­59 years old (55.9%) with >20 years of clinical experience (54.3%). 498 participants (98.4%) stated to perform RCT. Rubber dam was always used in 52.2% of GP, 69.9% of EI and 89.5% of ES, while never-user accounted for 14.1%. Overall, 63.9% used loupes and 13.7% microscopes (mostly by ES). Rotating instruments were selected in 43.2%, followed by conventional hand-instruments (37.8%) and reciprocating instruments (19%). GP rarely activated irrigants and applied NaOCl in lower concentrations (>0.5­1%) compared to ES. GP preferred lateral compaction (57%), ES performed vertical compaction in 89.5%. 92% completed RCT after two or more visits. The majority of dentists in Switzerland follow the available quality guidelines and the present findings are coherent with internationally published surveys. Nonetheless, discrepancies are still present between daily practice and endodontic quality guidelines, especially with the routine use of rubber dam and working length determination, predominantly within the endodontic non-specialists.

Tooth Repair and Regeneration.

PURPOSE OF REVIEW: Current dental treatments are based on conservative approaches, using inorganic materials and appliances.This report explores and discusses the newest achievements in the field of "regenerative dentistry," based on the concept of biological repair as an alternative to the current conservative approach. RECENT FINDINGS: The review covers and critically analyzes three main approaches of tooth repair: the re-mineralization of the enamel, the biological repair of dentin, and whole tooth engineering. SUMMARY: The development of a concept of biological repair based on the role of the Wnt signaling pathway in reparative dentin formation offers a new translational approach into development of future clinical dental treatments.In the field of bio-tooth engineering, the current focus of the researchers remains the establishment of odontogenic cell-sources that would be viable and easily accessible for future bio-tooth engineering.

The effects of crown venting or pre-cementing of CAD/CAM-constructed all-ceramic crowns luted on YTZ implants on marginal cement excess.

OBJECTIVES: The purpose of this study was to analyze the cement excess produced when cementing CAD/CAM-fabricated lithium disilicate (L) or zirconium dioxide (Z) crowns using adhesive cement (A) or resin-modified glass ionomer cement (B). Three different cementation techniques were applied: palatal venting (PV), pre-cementation with custom analogs (CA), and conventional standard procedure (SP). MATERIALS AND METHODS: Seventy-two crowns (36 each material) were assigned to 12 experimental groups depending on the restoration material (L, Z), type of cement (A, B), and cementation technique (PV, CA, SP). Weight measurements were taken during cementation, and the amounts of excess cement, cement retained in crown, and relative excess cement were calculated and statistically analyzed. RESULTS: A significant direct relation between the amounts of cement applied and excess cement was observed in groups CA and SP. Vented crowns showed least amounts of marginal excess cement (0.8 ± 0.3 µl) followed by CA (4.2 ± 1.1 µl) and SP (8.8 ± 2.5 µl; p < .001). In CA, 32.1% less excess cement (95%CI: 28.4, 35.7) was produced than in the SP group (p < .001), but 27.4% more than in the PV group (95%CI: 23.8,31.0; p < .001). Overall, slightly smaller amounts of adhesive cement (A) than of glass ionomer cement (B) were retained in crowns. CONCLUSIONS: Using crown venting was the most effective measure to reduce the amount of marginal excess cement, followed using a pre-cementation device. To keep the marginal excess cement of one-piece zirconia implants to a minimum, both techniques should be considered for clinical application.

Fracture behavior, marginal gap width, and marginal quality of vented or pre-cemented CAD/CAM all-ceramic crowns luted on Y-TZP implants.

OBJECTIVES: To investigate the fracture behavior and marginal gap region of CAD/CAM fabricated lithium disilicate (L) and zirconium dioxide (Z) crowns using palatal venting (PV), pre-cementation with custom analogs (CA), or conventional cementation technique (SP) with adhesive cement (A) or resin-modified glass ionomer cement (B). MATERIAL AND METHODS: Twelve groups (n = 6) were set according to material (L, Z), cement (A, B), and technique (PV, CA, SP). Specimens were thermo-mechanical aged (TML), loaded until fracture (LF) and fracture patterns recorded. Marginal gap width and quality were assessed and compared to replicas obtained before and after TML. RESULTS: Crown material significantly influenced LF with a mean of 1037.6 ± 282.4 N in L and 5356.3 ± 1207.0 N in Z groups (p < .001). Neither cement material nor cementation method affected the outcome. Fractures occurred along the mesial-distal central fissure in both materials. Gap width before TML was 22.04 ± 13.42 µm for L and 19.98 ± 12.72 µm for Z specimens, with overall no influence of crown material, cement type, or method. Marginal cleanliness just below the polished implant shoulder reached 66.7%-88.9% with A, and 91.7%-100% with B, and tended to increase in all groups during TML indicating a decrease in excess cement. Implant-crown junctions were cleaner with B compared to A (p ≤ .001) and along Z crown surfaces compared to L (p ≤ .007). CONCLUSIONS: Crown venting of lithium disilicate and zirconium dioxide crowns did not affect the fracture load and patterns. Complete cement removal was rare, and the observed particle ablation requires further clinical attention, particularly with submucosal margins.

Determinants of biofilm formation and cleanability of titanium surfaces.

OBJECTIVE: The aim of the present study was to analyze biofilm formation on four different titanium-based surfaces (machined titanium zirconium (TiZr) alloy, M; machined, acid-etched TiZr alloy, modMA; machined, sandblasted, acid-etched TiZr alloy, modSLA; and micro-grooved titanium aluminum vanadium alloy, TAV MG) in an experimental human model. MATERIAL AND METHODS: Custom-made discs were mounted in individual intraoral splint housings and worn by 16 volunteers for 24 h. The safranin staining assay, isothermal microcalorimetry (IMC), and SEM were applied before and after surface cleaning. RESULTS: The hydrophilic surfaces modMA and modSLA with greater surface micro-roughness exhibited significantly more biofilm than the hydrophobic surfaces TAV MG and M. The standardized cleaning procedure substantially reduced the biofilm mass on all surfaces. After cleaning, the IMC analyses demonstrated a longer lag time of the growth curve on TAV MG compared to modSLA. Inter- and intraindividual variations in biofilm formation on the titanium discs were evident throughout the study. CONCLUSIONS: Surface hydrophilicity and roughness enhanced biofilm formation in vivo, whereas surface topography was the most influential factor that determined surface cleanability. While the grooved surface retained larger amounts of initial biofilm, the machined surface was easier to clean, but proliferation indicated by increased metabolic activity (growth rate) in IMC occurred despite mechanical biofilm removal.

In vitro assessment of the tooth staining potential of endodontic materials in a bovine tooth model.

BACKGROUND/AIMS: Traumatized teeth requiring endodontic intervention may discolor as a result of the treatment performed. Thus, the aim was to investigate the discoloration potential of different endodontic cements, dressings, and irrigants used in dental traumatology. MATERIALS AND METHODS: Cylindrical cavities were prepared in 330 bovine enamel-dentine blocks (10 × 10 × 3.5 mm), leaving 2 mm of enamel and dentine on the labial side. The specimens were randomly assigned to 22 groups (n = 15). The cavities were filled with a range of endodontic materials, sealed with composite and stored in physiological saline. The color of the labial enamel surface was measured with a spectrophotometer at 7 time intervals: before (T0) and after the placement of the test material (T1 = baseline), after 1 week (T2), 1 month (T3), 3 months (T4), 6 months (T5), and 12 months (T6). The color difference values (ΔE) were calculated and further analyzed by anova and the Tukey-Kramer post hoc test (α = 0.05). RESULTS: After 12 months, significant staining was observed among the endodontic cements only in the Portland cement group with additional bismuth oxide (H-MED PC BiOx; ΔE 22.2). Specimens with other commercially available calcium silicate cements containing bismuth oxide were not significantly discolored. All specimens with endodontic dressings and irrigants were color stable except the tested triple antibiotic paste (M-TreVitaMix; ΔE 14.9) and the double antibiotic paste (N-BiMix; ΔE 14.9). Both mixtures did not contain tetracycline derivatives. CONCLUSIONS: The presence of bismuth oxide in calcium silicate cements was not shown to be a reliable predictor for tooth discoloration. Antibiotic pastes without tetracycline derivatives do not guarantee the color stability of teeth.

Influence of the bleaching interval on the luminosity of long-term discolored enamel-dentin discs.

OBJECTIVES: The aim of this study is to investigate the influence of changing the sodium perborate-tetrahydrate (PBS-4) at a 4-day interval versus no change after 16 days of internal bleaching. MATERIALS AND METHODS: Two hundred and ten bovine enamel-dentin discs were discolored for 3.5 years with 14 different endodontic materials. All groups with a discoloring index of ∆E (mean) ≥ 5.5 were included in the present investigation: ApexCal (APCA), MTA white + blood (WMTA+BL), Portland cement + blood (PC+BL), blood (BL), MTA gray (GMTA), MTA gray + blood (GMTA+BL), Ledermix (LED), and triple antibiotic paste containing minocycline (3Mix). Fourteen specimens of each group were randomly assigned into two treatment groups: (1) no change of the PBS-4 (n = 7); (2) change of the PBS-4 every 4 days (n = 7). Color measurements were taken at 10 different time intervals and the L*a*b* values were recorded with a spectrophotometer (VITA Easyshade® compact). RESULTS: In the group 3Mix, significantly better results were achieved by changing the bleaching agent every 4 days (P = 0.0049; q = 0.04), while the group WMTA+BL indicated better results by no change of the bleaching agent (P = 0.0222, q = 0.09). All remaining groups showed no statistical difference between the two treatment procedures. CONCLUSIONS: Moderate discolorations can be successfully treated without changing the bleaching agent over a period of 16 days. Changing the sodium perborate-tetrahydrate every 4 days is preferred in case of severe discolored enamel-dentin discs only. CLINICAL RELEVANCE: This approach may offer a reduced number of clinical appointments and a secondary cost reduction to the patient.

Antimicrobial activity of short- and medium-term applications of polyhexamethylene biguanide, chlorhexidine digluconate and calcium hydroxide in infected immature bovine teeth in vitro.

AIM: To compare the antimicrobial activity of polyhexamethylene biguanide (Prontosan wound gel, Pr) and chlorhexidine digluconate (CHX) after short- and medium-term application with the disinfection ability of calcium hydroxide (Ca) in a model using immature bovine teeth. METHODS: Sixty immature bovine roots were infected with Enterococcus faecalis and randomly assigned to six groups (n = 10). Disinfectants were applied into the root canal for 10 min (CHX-10 min and Pr-10 min) or 7 days (CHX-7d, Pr-7d and Ca-7d(g) ). In the negative control group (Co-n), no disinfectant was used. Dentine samples were collected, and the total count of bacteria and colony-forming units were determined. The log10 -transformed Colony-forming units (CFU) data were analysed using a Kruskal-Wallis test with post hoc Wilcoxon multiple-comparison tests. RESULTS: The application of disinfectants led to a significant reduction in CFUs in all groups compared with group Co-n. When compared to Ca-7d(g) , CHX-7d (P = 0.290), CHX-10 min (P = 0.963) and Pr-7d (P = 0.095) revealed no significant differences. Pr-10 min had a significantly higher CFU value than Ca-7d(g) (P = 0.0004), CHX-10 min (P = 0.0009) and Pr-7d (P = 0.0006). CONCLUSIONS: Within the limitations of this study, sufficient antimicrobial effect may be reached by a short-term application of CHX. For the application of 1% Prontosan wound gel, a medium-term use (7 day) is required, while short-term use (10 min) is less effective.