Root surface alterations following manual and mechanical scaling: A comparative study.

OBJECTIVES: The aim of this study was to investigate the morphological and surface roughness changes in dental root samples following periodontal scaling by hand curette, piezoelectric ultrasonic devices or a combination of these. METHODS: Twenty-four monoradicular teeth extracted as a result of periodontal disease were divided into 4 groups: Group A was treated by piezoelectric ultrasonic scaler Piezon® Master 400; Group P by piezoelectric ultrasonic scaler PiezoSmart® ; Group C using Gracey curette 7/8; Group AC by a combined technique of piezoelectric ultrasonic scaler Piezon® Master 400 and Gracey curette 7/8. The treated samples were then analysed using a white light interferometer and scanning electron microscopy (SEM). RESULTS: Roughness analysis revealed major surface alterations in Group C (Sa  = 24.98 µm); the samples treated using the combined technique (Group AC) showed reduced but still significant alteration (Sa  = 14.48 µm), while samples treated with the piezoelectric ultrasonic devices (Group A and Group P) presented the lowest roughness values (Sa  = 8.99 and Sa  = 4.45 µm, respectively). A significant difference was found between groups C and P (P = 0.036). SEM analysis confirmed the roughness analysis revealing non-homogeneous surfaces in Group C, while a less morphological alteration was noted in the other groups. CONCLUSION: All periodontal devices used in this in vitro study produced a certain degree of surface alteration. Hand curettes appear to have a major impact on surface integrity compared with piezoelectric ultrasonic devices.

Evaluation of three different manual techniques of sharpening curettes through a scanning electron microscope: a randomized controlled experimental study.

OBJECTIVE: The purpose of this study was to compare the effectiveness of three different techniques for manually sharpening of periodontal curettes (PCs) by examining the blades with the aid of scanning electron microscope (SEM). METHODS: Three groups were considered based on three sharpening methods used: group A (moving a PC over a stationary stone); group B (moving a stone over a stationary PC) and group C (moving a PC over a stone fixed, placed on a 'sharpening horse'). After the sharpening, the blades were examined using SEM. The SEM images were assessed independently by five different independent observers. An evaluation board was used to assign a value to each image. A preliminary pilot study was conducted to establish the number of samples. Pearson's correlation test was used to assess the correlations between measurements. anova test with Bonferroni's post hoc test was used to compare the three groups. RESULTS: Sixty PCs (20 PCs per group) were used in this study. Statistically significant differences emerged between the three groups (P-value = 0.001). Bonferroni's test showed that the difference between groups A and B was not statistically significant (P-value = 0.80), while it was significant for the comparisons between groups A and C (P-value = 0.005) and between groups B and C (P-value = 0.001). CONCLUSIONS: The sharpening technique used in group C, which involved the use of the sharpening horse, proved the most effective.

Histological and profilometric evaluation of the root surface after instrumentation with a new piezoelectric device - ex vivo study.

OBJECTIVES: An ex vivo model was designed to profilometrically and histologically assess root changes resulting from scaling with a new ultrasonic device, designed for bone piezoelectric surgery, in comparison with curettes. METHODS: Three groups of 10 periodontal hopeless teeth were each subjected to different root instrumentation: Gracey curettes (CUR); ultrasonic piezoelectric device, Perio 100% setting, level 8 (P100); and ultrasonic piezoelectric device Surg 50% setting, level 1 (S50). After extraction, all teeth were photographed to visually assess the presence of dental calculus. The treated root surfaces were profilometrically evaluated (Ra, Rz, Rmax). Undecalcified histological sections were prepared to assess qualitative changes in cementum thickness. Statistical analysis was carried out using one-way anova test with a significance level of 95%. RESULTS: Both instruments proved to be effective in the complete removal of calculus. The CUR group presented the lowest Ra [2.28 µm (±0.58)] and S50 the highest [3.01 µm (±0.61)]. No statistically significant differences were detected among the three groups, for Ra, Rz and Rmax. Histologically, there was a cementum thickness reduction in all groups, being higher and more irregular in S50 group. CONCLUSIONS: Within the limits of this study, there were no statistically significant differences in roughness parameters analyzed between curettes and the ultrasonic piezoelectric unit. This new instrument removes a smaller amount of cementum, mainly at the Perio 100% power setting, which appears to be the least damaging. The ultrasonic device is effective in calculus removal, proving to be as effective as curettes.

Videoscope-assisted minimally invasive periodontal surgery (V-MIS).

AIM: Small incision surgery has become routine in many areas of medicine but has not been widely accepted in periodontal therapy. A videoscope to assist minimally invasive surgery (MIS) has been developed. The clinical outcomes from MIS performed using this videoscope (V-MIS) are reported. MATERIALS AND METHODS: Patients were evaluated for residual defects following non-surgical therapy consisting of root planing with local anaesthetic. Thirty patients having 110 sites with residual pocket probing depth (PPD) of at least 5 mm, 2 mm loss of clinical attachment level (CAL), and radiographic evidence of bone loss were surgically treated. V-MIS was performed utilizing the videoscope for surgical visualization. RESULTS: At re-evaluation 6 months post surgery, there was a statistically significant improvement (p < .001) in mean PPD and CAL (PPD 3.88 ± 1.02 mm, CAL 4.04 ± 1.38 mm) in 1, 2, and 3 wall defects. All PPD at re-evaluation were 3 mm or less. There was a mean post-surgical increase in soft tissue height (0.13 ± 0.61 mm, p = 0.168) with a decrease in recession. CONCLUSIONS: The improvement in PPD and CAL from V-MIS, in the authors' opinion, appears to be favourable when compared to previously reported results of periodontal regenerative surgery. The lack of post-surgical recession following V-MIS has not been reported with traditional regenerative surgery.

Clinical evaluation of chlorine dioxide for disinfection of dental instruments.

This study aimed to clinically evaluate the disinfection efficacy of chlorine dioxide (ClO2) for used dental instruments. An imprint culture technique demonstrated that ultrasonic cleaning of intraorally applied dental mirrors in 0.02% ClO2 for 10 minutes resulted in compete removal of microorganisms for 10 subjects. Hepatitis C virus (HCV) RNA was detected by real-time polymerase chain reaction on periodontal curettes after subgingival scaling in four HCV-infected patients and was completely removed by the same treatment procedure. Therefore, the combination of ultrasonic cleaning with ClO2 may provide an alternative to toxic disinfectants, such as glutaraldehyde and sodium hypochlorite, for disinfecting dental instruments.

A videoscope for use in minimally invasive periodontal surgery.

INTRODUCTION: Minimally invasive periodontal procedures have been reported to produce excellent clinical results. Visualization during minimally invasive procedures has traditionally been obtained by the use of surgical telescopes, surgical microscopes, glass fibre endoscopes or a combination of these devices. All of these methods for visualization are less than fully satisfactory due to problems with access, magnification and blurred imaging. CLINICAL INNOVATION: A videoscope for use with minimally invasive periodontal procedures has been developed to overcome some of the difficulties that exist with current visualization approaches. This videoscope incorporates a gas shielding technology that eliminates the problems of fogging and fouling of the optics of the videoscope that has previously prevented the successful application of endoscopic visualization to periodontal surgery. In addition, as part of the gas shielding technology the videoscope also includes a moveable retractor specifically adapted for minimally invasive surgery. DISCUSSION: The clinical use of the videoscope during minimally invasive periodontal surgery is demonstrated and discussed. CONCLUSION: The videoscope with gas shielding alleviates many of the difficulties associated with visualization during minimally invasive periodontal surgery.

Influence of nicotine and cotinine impregnation on the first step of periodontal regeneration: clot stabilization.

This study analyzes the clot stabilization on root surfaces of teeth impregnated with cotinine and nicotine and the influence of the scaling in the adhesion of blood components, observing the influence of new exposition to nicotine and/or cotinine after scaling. Fifteen human teeth extracted due to periodontal disease of non-smokers patients were selected and manually scaled. Four dentin blocks were obtained from each tooth (n = 60). Samples received blood application or reimpregnation with nicotine and/or cotinine, depending on the groups. Group 1: PBS immersion + root scaling + blood; group 2: nicotine + root scaling + blood; group 3: nicotine + root scaling + nicotine reapplication + blood; group 4: cotinine + root scaling + blood; group 5: cotinine + root scaling + cotinine reapplication+ blood; group 6: nicotine and cotinine + root scaling + nicotine and cotinine + blood. Samples were kept in 2 ml of each substance for 24 hours. Each group received a blood drop and was analyzed by SEM. The higher amount of blood components was present in teeth exposed to cotinine and the groups submitted to scaling and blood application in comparison with groups that received reapplication of toxic substances after scaling. The greater toxic effect on root dentin surface was after the exposure to nicotine and cotinine. Results suggest that periodontal healing may be delayed in smokers due to the direct inhibition of clot stabilization on the root surface when nicotine and cotinine are present concomitantly.

Comparative evaluation of oxygen saturation levels using pulse oxymeter during nonsurgical and surgical periodontal therapy in chronic periodontitis patients.

BACKGROUND AND AIM: Monitoring is the global method of observation and data recording in relation to body organ and system function that afford constant information to ensure continuous evalutation of the patient's physical condition. Basic monitoring provides essential information for assessing the vital signs, both circulatory and respiratory, and fundamentally comprises the control of blood pressure (BP) and heart rate (HR) and rhythm. Pulse oxymetry is used to record HR and oxygen saturation. The objective of the study was to assess and compare hemodynamic changes by monitoring oxygen saturation level changes during periodontal surgical and nonsurgical therapy. MATERIALS AND METHODS: A cross-sectional observational study was conducted in 30 chronic periodontitis patients. Patients were divided into two groups; Group A consisted of 15 patients undergoing surgical periodontal therapy, Group B consisted of 15 patients undergoing nonsurgical periodontal therapy. The hemodynamic changes were evaluated by monitoring HR and oxygen saturation level using pulse oxymeter (SaO2). HR and SaO2 were monitored continuously and registered pre-operatively, i.e. 10 minutes before the procedure, intra-operatively and postoperatively, i.e. 10 minutes after the procedure. One-way analysis of variance test (ANOVA) was performed for data analysis. RESULTS: Both the groups showed a slight fall in oxygen saturation levels intraoperatively, but within the normal range. More decrease in oxygen saturation levels was observed in nonsurgical periodontal therapy as compared to surgical periodontal therapy at intraoperative levels. The differences in the values were statistically significant. There was no statistical difference seen in the postoperative and preoperative values. CONCLUSION: Most of the hemodynamic changes induced during the periodontal therapy were within normal limits, taking into consideration the anxiety and stress produced by the surgical intervention. The hemodynamic change was more in nonsurgical as compared to surgical periodontal therapy.

A comparison of dental ultrasonic technologies on subgingival calculus removal: a pilot study.

PURPOSE: This pilot study compared the clinical endpoints of the magnetostrictive and piezoelectric ultrasonic instruments on calculus removal. The null hypothesis stated that there is no statistically significant difference in calculus removal between the 2 instruments. METHODS: A quasi-experimental pre- and post-test design was used. Eighteen participants were included. The magnetostrictive and piezoelectric ultrasonic instruments were used in 2 assigned contra-lateral quadrants on each participant. A data collector, blind to treatment assignment, assessed the calculus on 6 predetermined tooth sites before and after ultrasonic instrumentation. Calculus size was evaluated using ordinal measurements on a 4 point scale (0, 1, 2, 3). Subjects were required to have size 2 or 3 calculus deposit on the 6 predetermined sites. One clinician instrumented the pre-assigned quadrants. A maximum time of 20 minutes of instrumentation was allowed with each technology. Immediately after instrumentation, the data collector then conducted the post-test calculus evaluation. RESULTS: The repeated analysis of variance (ANOVA) was used to analyze the pre- and post-test calculus data (p≤0.05). The null hypothesis was accepted indicating that there is no statistically significant difference in calculus removal when comparing technologies (p≤0.05). Therefore, under similar conditions, both technologies removed the same amount of calculus. CONCLUSION: This research design could be used as a foundation for continued research in this field. Future studies include implementing this study design with a larger sample size and/or modifying the study design to include multiple clinicians who are data collectors. Also, deposit removal with periodontal maintenance patients could be explored.

Clinical evaluation of chlorhexidine and essential oils for adjunctive effects in ultrasonic instrumentation of furcation involvements: a randomized controlled clinical trial.

BACKGROUND: The aim of this clinical study was to evaluate and compare the clinical efficacy of subgingival ultrasonic mechanical instrumentation (UMI) irrigated with essential oils (EOs) and chlorhexidine (CHX) at the furcation involvements (FI). METHODS: Forty-five patients (244 FI) who presented with Class II FI were recruited to the study. Patients were randomly assigned to CHX (UMI irrigated with 0.2% CHX), EO (UMI irrigated with EOs) or control (UMI irrigated with distilled water) groups. All treatments were performed in one session. For all groups, plaque index (PI), gingival index (GI), position of gingival margin (PGM), pocket depth (PD), bleeding on probing (BOP), clinical attachment level (CAL) and horizontal attachment level (HAL) scores were recorded at baseline and 1 and 3 months after therapy. RESULTS: In all groups, there were significant reductions in PI, GI, PD and BOP, increase in PGM scores and gain in CAL and HAL scores, at 1 and 3 months compared to baseline. Except in BOP scores, there were no significance differences among the groups at any time point. At 1 and 3 months, there were significant reductions in the BOP scores of the EO group compared with the CHX and control groups. CONCLUSION: Within the limits of this study, the use of EOs as a cooling liquid of UMI may promote slight adjunctive effects at FI compared to CHX and water.

Effect of instrumentation using curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser on the morphology and adhesion of blood components on root surfaces: a SEM study.

This study used scanning electron microscopy (SEM) to evaluate the morphology and adhesion of blood components on root surfaces instrumented by curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser. One hundred samples from 25 teeth were divided into 5 groups: 1) Curettes; 2) Piezoelectric ultrasonic scaler; 3) Curettes plus piezoelectric ultrasonic scaler; 4) Er,Cr:YSGG laser; 5) Curettes plus Er,Cr:YSGG laser. Ten samples from each group were used for analysis of root morphology and the other 10 were used for analysis of adhesion of blood components on root surface. The results were analyzed statistically by the Kruskall-Wallis and Mann-Whitney tests with a significance level of 5%. The group treated with curettes showed smoother surfaces when compared to the groups were instrumented with piezoelectric ultrasonic scaler and the Er,Cr:YSGG laser. The surfaces instrumented with piezoelectric ultrasonic scaler and Er,Cr:YSGG laser, alone or in combination with hand scaling and root planing, did not differ significantly (p>0.05) among themselves. No statistically significant differences (p>0.05) among groups were found as to the adhesion of blood components on root surface. Ultrasonic instrumentation and Er,Cr:YSGG irradiation produced rougher root surfaces than the use of curettes, but there were no differences among treatments with respect to the adhesion of blood components.

Subgingival ultrasonic instrumentation of residual pockets irrigated with essential oils: a randomized controlled trial.

AIM: To evaluate the clinical efficacy of subgingival ultrasonic instrumentation irrigated with essential oils (EOs) of residual periodontal pockets. MATERIAL AND METHODS: Sixty-four individuals with chronic periodontitis were invited to participate in this randomized, double-blind, parallel, and placebo-controlled clinical trial. All subjects received non-surgical periodontal therapy. After re-evaluation (baseline), residual pockets (pocket depth ≥5 mm) received test (ultrasonic instrumentation irrigated with EOs) or control therapy (ultrasonic instrumentation irrigated with negative control). Probing pocket depth (PPD), gingival recession (R), clinical attachment level (CAL), bleeding on probing (BOP), and plaque were assessed at baseline and after 4, 12, and 24 weeks. Differences between groups and changes over the course of time were analysed according to a generalized linear model. RESULTS: There was a significant reduction in PPD and BOP, as well as a significant CAL gain in the two groups (p<0.001). Nevertheless, there were no differences between the groups at any time of the study. When only initially deep pockets (PPD ≥7 mm) were analysed, a significantly greater CAL gain (p=0.03) and PPD reduction (p=0.01) was observed in the test group. CONCLUSION: The adjunctive use of EOs may promote significant CAL gain and PPD reduction in deep residual pockets.

Gingival curettage study comparing a laser treatment to hand instruments.

The purpose of this clinical study was to examine nonsurgical treatments of periodontal disease comparing a diode laser to subgingival curettage with conventional hand instruments. The study group comprised 18 patients with moderate periodontal degradation who were treated without local anesthesia. Each quadrant was randomly allocated in a split-mouth design either to treatment with a 810-nm diode laser using an energy of 2 W (test group) or to gingival curettage using hand instruments (control group). Clinical data, including plaque index (PI), gingival index (GI), sulcus bleeding index (SBI), pocket depth (PD), clinical attachment level (CAL) and visual analog scale (VAS) score were acquired prior to and 4 weeks after treatment. The treatment time for each tooth was also recorded. The results demonstrated a statistically significant reduction of the GI, SBI and PD and a significant gain in CAL in both groups after 4 weeks. However, there were no significant differences between the test and control groups for the above data. The score for the degree of treatment discomfort was significantly lower and the average treatment time was significantly less in the test group than in the control group. Diode laser subgingival curettage resulted in statistically significant improvements in PD, SBI, GI and CAL with less discomfort and treatment time compared to treatment with the hand instruments.

Effect of instrumentation using curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser on the morphology and adhesion of blood components on root surfaces: a SEM study

This study used scanning electron microscopy (SEM) to evaluate the morphology and adhesion of blood components on root surfaces instrumented by curettes, piezoelectric ultrasonic scaler and Er,Cr:YSGG laser. One hundred samples from 25 teeth were divided into 5 groups: 1) Curettes; 2) Piezoelectric ultrasonic scaler; 3) Curettes plus piezoelectric ultrasonic scaler; 4) Er,Cr:YSGG laser; 5) Curettes plus Er,Cr:YSGG laser. Ten samples from each group were used for analysis of root morphology and the other 10 were used for analysis of adhesion of blood components on root surface. The results were analyzed statistically by the Kruskall-Wallis and Mann-Whitney tests with a significance level of 5 percent. The group treated with curettes showed smoother surfaces when compared to the groups were instrumented with piezoelectric ultrasonic scaler and the Er,Cr:YSGG laser. The surfaces instrumented with piezoelectric ultrasonic scaler and Er,Cr:YSGG laser, alone or in combination with hand scaling and root planing, did not differ significantly (p>0.05) among themselves. No statistically significant differences (p>0.05) among groups were found as to the adhesion of blood components on root surface. Ultrasonic instrumentation and Er,Cr:YSGG irradiation produced rougher root surfaces than the use of curettes, but there were no differences among treatments with respect to the adhesion of blood components.

Esse estudo utilizou microscopia eletrônica de varredura (MEV) para avaliar a morfologia e a adesão de elementos sanguíneos em superfícies radiculares instrumentadas com curetas, ultrassom piezoelétrico e laser de Er,Cr:YSGG. Foram utilizadas no presente estudo 100 amostras provenientes de 25 dentes que foram divididas em 5 grupos: 1) Raspagem manual com curetas; 2) Raspagem com ultrassom; 3) Associação instrumento manual e ultrassom; 4)Irradiação do laser de Er,Cr:YSGG;5)Associação raspagem manual com irradiação com laser de Er,Cr:YSGG. Dez amostras de cada grupo foram utilizadas para análise da morfologia e as outras 10 foram utilizadas para a análise de adesão de elementos sanguíneos. As eletromicrografias foram analisadas através dos escores de adesão de elementos sanguíneos e pelo índice de morfologia radicular e os resultados foram analisados estatisticamente através dos testes de Kruskall-Wallis e de Mann-Whitney com nível de significância de 5 por cento. O grupo que foi tratado com instrumentos manuais apresentou superfície mais lisa em relação aos grupos que foram instrumentados com ultrassom e com o laser de Er,Cr:YSGG. As superfícies instrumentadas com ultrassom e com o laser de Er,Cr:YSGG de forma isolada ou associada a raspagem manual não apresentaram diferenças estatísticas entre si (p>0,05). Não houve diferenças estatísticas entre os grupos em relação a adesão de elementos sanguíneos(p>0,05). A instrumentação ultrassônica e a irradiação com o laser de Er,Cr:YSGG produziram superfícies radiculares mais rugosas em relação a raspagem com curetas, porém não houve diferenças entre os tratamentos com relação à adesão de elementos sanguíneos.

Patients' perception of pain during ultrasonic debridement: a comparison between piezoelectric and magnetostrictive scalers.

PURPOSE: To compare patients' perception of discomfort, vibration and noise levels between piezoelectric and the magnetostrictive ultrasonic units during periodontal debridement. METHODS: Periodontal debridement was performed on 75 subjects using a split-mouth design. Two quadrants on the same side were instrumented with a piezoelectric ultrasonic device (EMS Swiss Mini Master® Piezon) and the remaining 2 quadrants were instrumented with a magnetostrictive ultrasonic device (Dentsply Cavitron® SPS™). Subjects marked between 0 and 100 along a visual analog scale (VAS) for each of the 3 variables immediately after treatment of each half of the dentition. Scores of the VAS were compared using a nonparametric test for paired data, the Wilcoxon Signed-Rank test. The level of significance was set at p<0.05. Descriptive statistics included the median and the first and third quartiles as a measure of variation. RESULTS: Mean scores for patient discomfort and vibration were greater for the magnetostrictive device at p=0.007 and p=0.032, respectively. The scores for noise level between the 2 ultrasonic types were almost equal. CONCLUSION: The results show that, on average, patients in this study prefer instrumentation with the piezoelectric as it relates to awareness of associated discomfort and vibration. The results of this study may assist the clinician in the decision over which ultrasonic device may prove more beneficial in decreasing patient discomfort and increasing patient compliance.

Seeing the Light--the truth about soft tissue lasers and nonsurgical periodontal therapy.

Although laser treatment has generated considerable interest among dentists and the public, there is no evidence that any laser system adds clinical value over and above scaling and root planing and conventional surgical treatment for periodontitis. Following a brief explanation of the mechanism behind soft tissue lasers, the evidence on the use of laser therapy in addition to traditional nonsurgical periodontal treatment in the management of periodontal diseases is reviewed.

Subgingival plaque removal using a new air-polishing device.

BACKGROUND: The purpose of this study is to evaluate the safety, patient acceptance, and short-term microbiologic effect of a new air-polishing device in subjects in maintenance care with residual pockets > or =5 mm. METHODS: This was an examiner-masked, randomized, split-mouth clinical trial. A new disposable nozzle, allowing the subgingival application of amino acid glycine powder at a limited pressure, was compared to scaling and root planing (SRP) in 50 subjects with residual pockets during the maintenance phase. After removing supragingival deposits, the spray was applied for 4 to 5 seconds in all sites > or =5 mm in the test quadrant, whereas SRP was used in the control quadrant. Microbiologic samples were taken from one treated test and one control site 2 days before and 7 days after treatment. Total bacterial counts and the counts of six periodontal pathogens were determined by real-time polymerase chain reaction. RESULTS: No adverse event was noted in any subject for the test or control treatment. Using a visual analog scale, the patients perceived the test treatment to be significantly less painful/uncomfortable than the hand instrumentation (P <0.001). Significantly less time was used by the operator for the test procedure (P <0.001). The reduction in bleeding on probing was significant for the treated sites in the test and control quadrants (P = 0.019 and P <0.001, respectively), but traditional SRP reduced the bleeding tendency significantly more than air polishing (P = 0.045). The differences in the total bacterial load and the counts of six periodontal pathogens between the test and control sites did not reach statistical significance. The longitudinal reduction was significant in control sites for total bacteria load (P <0.001), Porphyromonas gingivalis (P = 0.01), Treponema denticola (P <0.001), and Tannerella forsythia (previously T. forsythensis) (P <0.001). CONCLUSION: Subgingival air polishing with a new device was safe (no adverse events were noted), perceived to be more acceptable by the patients, and was more time-efficient than SRP; however, on a microbiologic level, it was not superior to conventional SRP.

Molar furcation entrance and its relation to the width of curette blades used in periodontal mechanical therapy.

AIM: The purpose of this research was to evaluate molar furcation entrances and the width of periodontal curette blades used in periodontal instrumentation. MATERIALS AND METHODS: One hundred extracted molars (50 upper and 50 lower) were analysed. The furcation entrances were measured using orthodontic wires of different predetermined diameters: 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9 mm. McCall 17-18, Gracey 5-6 and Gracey 5-6 mini-five curette blades were measured at their anterior (AT), middle (MT) and posterior (PT) thirds by a single trained investigator, through the use of a digital caliper. RESULTS: The results showed significant differences (P < 0.0001) in relation to furcation entrances. The buccal upper molar furcations showed the narrowest dimensions. In relation to the blade diameter, significant differences among the instruments were found for their MT and PT (P < 0.0001), but not for the AT (P = 0.183). Significant differences were found among curette manufacturers. Nineteen per cent of evaluated furcations presented entrances <0.60 mm and 75% of the blades at their AT presented width >0.60 mm. CONCLUSIONS: These findings demonstrated that some molar furcation entrances could not be adequately instrumented with the tested curettes. The use of other hand instruments, such as periodontal files, rotating instruments and ultrasonic devices should be taken into consideration during periodontal therapy.