A morphological and micro-tensile bond strength evaluation of a single-bottle adhesive to caries-affected human dentine after four different caries removal techniques

OBJECTIVES: This study evaluated the influence of different caries removal techniques (conventional bur; chemomechanical removal/Carisolv()-MediTeam; a sonic preparation system/SonicsysMicro-Kavo and air abrasion/PrepStar-Danville Engineering) on microtensile bond strength to caries-affected human dentine. METHODS: Occlusal surfaces of extracted human permanent third molars with coronal dentine caries extending approximately halfway through the dentine was ground perpendicular to the long axis of the tooth to expose a flat surface of normal dentine surrounding the carious lesion with laser fluorescence values of approximately 30 (DIAGNODent), KaVo). Carious lesions were excavated with one of the four techniques until laser fluorescence values decreased to 15 in the center of the lesions. An ethanol-based dentine adhesive (Single Bond, 3M) was used to bond composite resin (P60, 3M) to the substrate. Vertical slices (n=11/group), approximately 0.8 mm thick were made through the caries-affected portions of each tooth, perpendicular to the bonding surface. Specimens were subjected to tensile stress at a crosshead speed of 1 mm/min. Data were analyzed by Kruskal-Wallis test. SEM investigation was performed for the qualitative evaluation of resin-dentine hybridization. RESULTS: The microtensile bond strengths were as follows (mean+/-SD in MPa): 6.4+/-5.3 (bur), 8.4+/-3.3 (Carisolv), 8.5+/-5.9 (Sonicsys Micro), and 8.8+/-8.8 (air abrasion). Statistical analysis did not show significant differences between any of the treatment modalities (p=0.160). Tensile fracture was cohesive within caries-affected dentine in all specimens. CONCLUSIONS: The four different caries removal techniques used within this study did not influence the bond strength of the tested dentine adhesive to caries-affected human dentine.     

Fluorescence-controlled Er:YAG laser for caries removal in permanent teeth: a randomized clinical trial

The aim of this randomized clinical study was to compare the efficacy of a fluorescence-controlled erbium-loaded yttrium aluminum garnet (Er:YAG) laser with conventional bur treatment for caries therapy in adults. Twenty-six patients with 102 carious lesions were treated using either the Er:YAG laser, at threshold levels of 7, 8, 9, and 10 [U], or rotary burs. Both techniques were applied to each lesion at separate locations. After treatment, dentine samples were obtained using a carbide bur. The viable counts of Streptococcus mutans (SM) and lactobacilli (LB) [expressed as colony-forming units (log10 CFUs)], treatment time, pain, vibration, and sound intensity were determined. The median numbers of CFUs for SM and LB were not statistically different between laser and bur treatment at threshold levels 7 and 8 [U]. At threshold levels 9 and 10 [U], the median number of CFUs for LB [1.11 (range: 0.00–2.04)] were significantly higher following laser treatment than following bur treatment [0.30 (range: 0.00–0.60)]. The results indicate that treatment with a fluorescence-controlled Er:YAG laser at threshold levels of 7 and 8 removed caries to a level similar to that achieved using conventional bur treatment, with clinically irrelevant amounts of remaining bacteria. Although more time consuming, laser treatment provided higher patient comfort than bur treatment.     

Performance of four dentine excavation methods in deciduous teeth

This in vitro study aimed to assess the speed and caries removal effectiveness of four different new and conventional dentine excavation methods. Eighty deciduous molars were assigned to four groups. Teeth were sectioned longitudinally through the lesion centre. Images of one half per tooth were captured by light microscope and confocal laser scanning microscopy (CLSM) to assess the caries extension. The halves were then reassembled and caries removed using round carbide bur (group 1), Er:YAG laser (group 2), hand excavator (group 3) and a polymer bur (group 4). The time needed for the whole excavation in each tooth was registered. After excavation, the halves were photographed by light microscope. Caries extension obtained from CLSM images were superimposed on the post-excavation images, allowing comparison between caries extension and removal. The regions where caries and preparation limits coincided, as well as the areas of over- and underpreparation, were measured. Steel bur was the fastest method, followed by the polymer bur, hand excavator and laser. Steel bur exhibited also the largest overpreparation area, followed by laser, hand excavator and polymer bur. The largest underpreparation area was found using polymer bur, followed by laser, hand excavator and steel bur. Hand excavator presented the longest coincidence line, followed by polymer and steel burs and laser. Overall, hand excavator seemed to be the most suitable method for carious dentine excavation in deciduous teeth, combining good excavation time with effective caries removal.     

Microhardness as a predictor of sound and carious dentine removal using alumina air abrasion

Clinical air abrasion is known to remove dental hard tissues effectively. The aim of this study was to quantify and compare the efficiency of alumina air abrasion in the removal of sound and carious dentine. Twelve non-cavitated carious lesions in freshly extracted molars were bisected mesiodistally. The Knoop hardness number (KHN) was measured on the cut sample surface at 250-microm intervals along a line running axially through the centre of the lesion, from the enamel-dentine junction to the pulp including both sound and carious tissue. The cut surface was then abraded over the same path using alumina particles (27 microm). Powder flow rates, pressure, distance and the angle of the nozzle to the tooth were kept constant throughout the experiment. Non-contact surface profilometry and surface analysis software were used to calculate the rate of dentine removal at the site of each KHN measurement. The results showed that dentine Knoop hardness can be used as a predictor of the rate of dentine removal, with a Somers' D value of 0.826. Carious dentine with a low KHN was removed less efficiently than the hard sound dentine with a higher KHN. Thus, dentists should be aware that air abrasion systems using alumina particles remove healthy dentine more efficiently than carious dentine, with the associated implications for clinical caries excavation and cavity preparation.     

Resin adhesion to caries-affected dentine after different removal methods

BACKGROUND: Caries-affected dentine is the common bonding substrate when treating a patient. At present, there are many methods used for caries removal. The aim of this study was to evaluate the microtensile bond strength of two adhesives (Clearfil Protect Bond and OptiBond Solo Plus Total-Etch) to caries-affected dentine after three different caries removal methods. METHODS: Extracted carious human third molars were used and caries-affected dentine surfaces were obtained from one of the three removal methods: (i) round steel bur in a slow-speed handpiece; (ii) Er:YAG laser; or (iii) 600-grit silicon carbide abrasive paper. Each of the adhesives was used to bond resin composite to the caries-affected dentine according to the manufacturers' instructions. Hourglass-shaped specimens were prepared and stressed in tension at 1mm/min. Data were analysed using two-way analysis of variance and least significant difference test. RESULTS: Clearfil Protect Bond showed significantly lower bond strength than OptiBond Solo Plus Total-Etch after caries removal with round steel bur, but the opposite was found for specimens treated with silicon carbide abrasive paper. For laser-treated dentine, no significant differences between the adhesives were revealed. CONCLUSIONS: Besides the differences in adhesives, different caries removal methods seem to influence resin adhesion to caries-affected dentine.     

In vitro evaluation of five alternative methods of carious dentine excavation

This in-vitro, split-tooth study aimed to evaluate the efficiency (time taken) and effectiveness (quantity of dentine removed) of four techniques of carious dentine excavation (bur, air-abrasion, sono-abrasion and Carisolv gel) compared to conventional hand excavation. Eighty freshly extracted human molars were assigned to four experimental groups (n = 20), sectioned longitudinally through occlusal lesions and pre-excavation colour photomicrographs obtained. Using the natural autofluorescence of carious dentine (detected using confocal laser scanning microscopy) as an objective and reproducible guide, carious dentine removal was assessed in each half of the split tooth sample, comparing hand excavation to the test method. The time taken to reach a cavity floor that was hard to a dental probe was noted and final colour photomicrographs were taken. From the results, it was concluded that bur excavation was quickest but overprepared cavities relative to the autofluorescent signature, whereas Carisolv excavation was slowest but removed adequate quantities of tissue. Sono-abrasion tended to underprepare whereas air-abrasion was more comparable to hand excavation in both the time and amounts of dentine removed. Conventional hand excavation appeared to offer the best combination of efficiency and effectiveness for carious dentine excavation within the parameters used in this study.     

Patient preference: conventional rotary handpieces or air abrasion for cavity preparation

It has been suggested that patients should accept the use of the air abrasion technique over the conventional handpiece due to the reduced need for anesthesia. Technologies for both air abrasion and the conventional rotary handpiece have, in recent decades, seen major improvements, but there are no recent scientific publications that evaluate the patient's preference for these two technologies when performing a cavity preparation. This study determined the patient's preference for air abrasion or the rotary handpiece for removing occlusal fissure carious lesions in mandibular premolars. Ten healthy subjects 18 years of age or older were recruited from the General Dentistry Clinic of the University of Rochester Eastman Dental Center, with fissure caries at a DEJ depth of similar size (determined by radiographs and clinical examination) in any two mandibular premolars in opposite quadrants. Within each subject, the two methods of caries removal were randomly assigned. In one premolar, air abrasion was used for cavity preparation, and in the other premolar, a conventional rotary handpiece was used. At each visit prior to treatment, the patients were instructed to complete the Emotional Status (ES) questionnaire (SUNY University at Buffalo Craniofacial Pain Clinic) to assess differences in their emotional status between appointments. At each appointment, when the restorative treatment was completed, patients were instructed to rate their pain on the Visual Analogue Scale (VAS). A technique preference questionnaire was given after the second appointment. The subjects rated the perception of pain as significantly lower (p < 0.05) when using air abrasion (6.0 mm versus 29.6 mm). All of the patients preferred air abrasion over conventional rotary handpieces. None of the patients required anesthesia and there was no indication that the emotional status influenced the result. Air abrasion was the preferred method of cavity preparation when removing fissural caries in mandibular premolars and most subjects did not experience any pain when air abrasion was used.     

Pain prediction for preventive non-operative management of dentinal caries in primary teeth in general dental practice

OBJECTIVES: To provide a pain-predictive model for the non-operative management of carious deciduous teeth from the analysis of data from a retrospective analysis of clinical case notes of children regularly attending two general dental practices and receiving preventive care. DESIGN: A clearly defined protocol was used to determine the fate of deciduous teeth diagnosed as carious into dentine but symptomless and left unrestored from the sequential examination of the clinical records of 480 children attending at least annually. RESULTS: The age of the children at the first visit when carious teeth were diagnosed ranged from 008 to 12.3 years, with the majority of children (243/480) presenting by 6 years of age. In all, 250 teeth from 162 children were extracted because of pain or became painful and were treated. The remaining 318 children did not report pain on subsequent visits. The strongest predictor of pain was age on diagnosis, the other factors being tooth type and extent of the cavity when first seen. Data from the present study provides a model that enables a child with deciduous caries to be placed into one of six pain-predictive groups associated with a risk of pain or infection if the teeth are not restored but provided with preventive care only. CONCLUSIONS: In these patients, the majority of unrestored carious deciduous teeth remain symptomless until shed. A higher risk of subsequent pain or infection was associated with the development of caries in younger patients, disease extending beyond single surfaces, and disease in lower deciduous molars. The results provide evidence to aid the treatment planning of carious deciduous teeth in children receiving regular preventive dental care.     

Determination of residual dentine caries after conventional mechanical and chemomechanical caries removal with Carisolv

The aim of the study was to assess the efficacy of removing dentine caries chemomechanically with Carisolv and with round burs. In 24 extracted permanent teeth each, caries removal with Carisolv or rotating round burs was monitored by checking the hardness of the dentine with a dental explorer and stopped at 12 teeth in each group when either (a) a leather-hard texture was reached or (b) a sharp scratching sound was heard. After embedding and sectioning (400 microm), caries activity of the remaining dentine was assessed using methyl red dye. In microscope images (7x) of the samples, the mean depth of the pink (caries-active, pH<5.5) and yellow (pH>5.5) staining of each carious lesion was calculated. Using a round bur, the depth of caries-active and -inactive lesions was significantly greater when a leather-hard texture (51-58 microm) was reached than when a sharp scratching sound was reached (19-25 microm, t-test, P<0.05). For teeth treated with Carisolv, only the depth of the caries-inactive dentine differed significantly. Regardless of the clinical criterion for caries removal, Carisolv treatment resulted in higher mean depths of caries-active dentine (71-78 microm) than conventional caries removal using the round bur (19-51 microm), while the mean depths of the caries-inactive dentine differed minimally. Thus, caries removal with Carisolv leaves up to a mean of 50 microm more carious dentine than round burs.     

Pain experience after conventional, atraumatic, and ultraconservative restorative treatments in 6- to 7-yr-old children

The hypothesis was tested that the level of pain experienced by children during conventional restorative treatment is higher than during atraumatic restorative treatment (ART) or an ultraconservative treatment. The sample consisted of 244 children, 6- to 7 yr of age, who had at least two teeth with dentine carious lesions. Before the first treatment session (Tx-1), in which one of the carious teeth was treated using one of the treatments, the level of dental anxiety was assessed using the Facial Image Scale (FIS). The child reported the intensity of pain experienced during the procedure using the Wong-Baker FACES Pain Rating Scale. When conventional restorative treatment was used, more children needed local anaesthesia. Analyses excluding the data of children who had received local anaesthesia showed no treatment group effect on the Wong-Baker score, a FIS Tx-1 effect on the Wong-Baker score, and a statistically significant correlation between FIS Tx-1 and Wong-Baker scores. There was no significant difference in the pain levels of children treated using conventional restorative treatment, atraumatic restorative treatment or ultraconservative treatment. Local anaesthesia had to be administered more frequently to children in the conventional restorative group than to those in the other two treatment groups.     

Carisolv化学机械去龋系统的临床评价

目的：评价Carisolv化学机械去龋系统的去龋时间、术中疼痛和近期疗效。方法：收集3～9岁儿童龋病患者80例,随机分为两组,每组40例,通过临床观察比较Carisolv化学机械去龋系统和常规车针去龋系统的去龋时间、术中疼痛、近期疗效。结果：窝洞制备时Carisolv较车针耗时要长（P〈0.05）,术中疼痛发生率有显著差异（P〈0．05）,近期疗效评价两组的差别无统计学意义（P〉0．05）。结论：Carisolv化学机械去龋系统可用于儿童龋病的治疗。     

An evaluation of polymer rotary instruments' ability to remove healthy, non-carious dentine

The aim of this study was to confirm that Smartprep burs do not cut non-carious, healthy dentine. Twenty non-carious extracted molars were trimmed with a diamond bur to remove enamel and to create a flat dentine surface. A new Smartprep bur (RA # 4) was applied to each tooth for 30 seconds. As a control, a new number three round stainless steel bur was applied to each tooth. The mean dentine loss was 4.25 mg (range 1.4 - 9 mg) for Smartprep burs and 12.21 mg (range 7.6 - 16.5 mg) for stainless steel burs. The Smartprep burs remove significantly less dentine than stainless steel burs.     

Desensitizing effects of an Er:YAG laser on hypersensitive dentine

AIM: The aim of the present study was to evaluate and compare the desensitizing effects of an Er:YAG laser (KEY II(R), KaVo, Germany) and Dentin Protector (Vivadent, Germany) on cervically exposed hypersensitive dentine. METHOD: A group of 30 patients showing a total of 104 contralateral pairs of hypersensitive and caries-free teeth was selected and randomly allocated in a split-mouth design to either (1) Er:YAG laser (80 mJ/pulse, 3 Hz), or (2) the application of Dentin Protector (polyurethane-isocyanate 22.5%; methylenechloride 77.5%) whereat one pair served as an untreated control in each patient. The degree of sensitivity to a thermal stimulus was determined qualitatively with an evaporative stimulus defined as a 3-s air blast at a distance of 2 mm from each site to be tested. A qualitative registration of the degree of discomfort was determined according to an arbitrary pain scale in 4 degrees. Recordings were assessed before treatment, immediately after, 1 week, 2 and 6 months after treatment by 1 blinded examiner. RESULTS: Both treatment forms resulted in significant improvements of discomfort immediately after and 1 week post treatment. After 2 months, the discomfort in the Dentin Protector(R) group increased up to 65% of the baseline score and even up to 90% after 6 months, whereas the effect of the laser remained at the same level that was achieved immediately after treatment. The differences immediately after, 1 week, 2 and 6 months post treatment between both groups were statistically high significant (p< or =0.001; respectively). Compared to the untreated control group, both treatment forms resulted in a significant reduction of discomfort at each follow-up examination. CONCLUSION: It was concluded that desensitizing of hypersensitive dentine with an Er:YAG laser is effective and the maintenance of the positive result was more prolonged than with Dentin Protector.     

An X-ray microtomography study on the mineral concentration of carious dentine removed during cavity preparation in deciduous molars

Dentists use a number of criteria in order to assess when a cavity is caries free, amongst which hardness is probably the most widely used. However, the judgement is subjective. X-ray microtomography (XMT) is a non-destructive microscopic technique that allows in vitro specimens to be scanned, manipulated and then rescanned. In this study, a high-definition XMT scanner was used to determine the mineral distribution of carious dentine in 10 deciduous molars, and the extent of dentine removed by an experienced clinician was investigated. For each tooth, after an initial XMT scan, caries was removed using a steel bur in a slow hand-piece. The tooth was then repositioned and rescanned. Mineral concentrations were calculated from the linear attenuation coefficients assuming the mineral phase to be hydroxyapatite and the organic phase to be collagen. The volume of dentine tissues removed was calculated by subtracting data of the second scan from the first. The results showed that the mean modal mineral concentration for the 10 teeth was 1.42 g x cm(-3) for sound dentine. Because of uncertainty about collagen concentration in carious dentine, the mean modal mineral concentration for the carious dentine had a range of 0.37-0.5 g x cm(-3). It was found that the subjective criteria used by the operator could lead to inconsistency of cavity preparation. The cavities could be overprepared by 8.5-44.3% in volume. However, the overpreparation was not uniform throughout the cavity: residual demineralised dentine could still be detected in the postoperative scan in isolated regions.     

Effects of potassium ions on dentine sensitivity in man

OBJECTIVE: To determine the effect of applying 500 mmol/l KCl at a pressure of 150 mm Hg above atmospheric to exposed dentine on pain sensation evoked by probing and air blast stimuli in human subjects. DESIGN: The experiments were carried out on 14 pairs of premolars in 14 human subjects (aged 17-30 years). Dentine was exposed at the tip of the buccal cusp, etched with acid and covered with saline, then 500 mmol/l KCl in Ringer's was applied at a pressure of 150 mm Hg for 4 min. Mechanical probing and air-drying stimuli were performed before and 2, 10, 20, 30 min after applying the KCl solution. The subject indicated the intensity of any pain produced on a visual analogue scale (VAS). Pulpal blood flow was recorded with a laser Doppler flow meter. Exactly the same procedure was carried out on the contralateral tooth except that 500 mmol/l NaCl in Ringer's was used in place of the KCl solution. RESULTS: The pain responses to mechanical probing and air blast stimuli were significantly reduced during the first 10 min after applying the KCl but not the NaCl solution. Pulpal blood flow did not change significantly after either treatment. CONCLUSION: Potassium ions, when applied to exposed dentine at a pressure of 150 mm Hg above atmospheric, produced temporary block of impulse conduction in sensory nerve endings in the dentine or pulp.     

Effect of resin coating on dentine compared to repeated topical applications of fluoride mouthwash after an abrasion and erosion wear regime

OBJECTIVES: The role of fluoride in preventing erosion and abrasion on dentine remains unclear. The aim of this study was to investigate the effect of repeated applications of a 0.05% fluoride mouthwash and an adhesive on wear of dentine using stainless steel discs reference points and a laser profilometer. METHODS: Small stainless steel discs were bonded to 60 caries free extracted molars which had previously been sectioned horizontally. The teeth were equally divided and subjected to four modalities in an erosion and abrasion laboratory model. Step heights were measured from the metal discs using a non-contacting laser profilometer at 100, 500, 1000, 2500 and 5000 cycles. RESULTS: The results after 5000 cycles showed that dentine coated with a dentine adhesive (0.015 microm, S.D. 0.090) had statistically less wear than fluoride (0.127 microm, S.D. 0.150), abrasion and erosion (0.182 microm, S.D. 0.150) or abrasion only (0.096 microm, S.D. 0.090) (p<0.001). CONCLUSION: In conclusion dentine surfaces coated with a resin-based adhesive provided more protection against erosion and abrasion than a fluoride mouthrinse. There were no statistical differences between the modalities for cycles less than 5000.     

The rôle of a dentine-bonding agent in reducing cervical dentine sensitivity

Abstract. This double-blind split-mouth trial with 16 adult patients investigated the ability of a dentine bonding agent (DBA) to reduce cervical dentine sensitivity. Following stimulation of pairs of teeth by conventional tactile and air blast stimuli, together with controlled evaporative and cold fluid stimuli, sensitivity was recorded using tactile threshold, visual-analogue scale (VAS) and short-form McGill pain questionnaire (SFMPQ), prior to and 1 week following treatment with DBA. Prior to assessment, subjects recorded their perceived overall sensitivity using VAS and SFMPQ. Application of each stimulus was separated by 10 min. Sensitivity was recorded by a clinician blinded to the treatment status of each tooth. The control tooth was treated by applying DBA to coronal enamel. Dietary information was collected after the post-treatment assessment. There was a significant ( p <0.05) improvement in tactile threshold and air flow and air blast VAS scores, together with reductions in sensitivity to evaporative stimuli when assessed by SFMPQ. Treatment response was not influenced by the subjects'age, gender, diet, use of fluoride-containing or silica-based toothpastes or fluoride mouthwashes, or a history of previous sensitivity treatment. It is concluded that topical application of DBA is an effective way to reduce cervical dentine sensitivity.     

激光及高压喷砂磨牙法的疼痛度评价

比较3种不同方式磨牙的疼痛度,探讨应用激光和高压喷砂实现无痛磨牙的可行性。方法：对同一患者分别采用YAG激光和常规机械法,或高压喷砂和常规机械法去龋制洞,让患者在0～10的疼痛度评价尺土选择所感受的疼痛度。结果：在20人的观察组中,3种方式都可以有效地去除塘坏组织。机械磨切组疼痛感者为75％;激光磨切组疼痛感者为30％;高喷砂切削组疼痛患者为10％。采用激光和高压喷砂磨牙的疼痛人数和疼痛度都显著低于机械磨切组。结论：激光和高压喷砂是两种减轻磨牙疼痛的有效方式,有望替代常规机械法成为无痛磨牙技术。     

乳牙化学去龋法的细菌学研究

目的：比较化学去龋法和机械去龋法清除细菌的效果。方法：选取40个龋坏深至牙本质的乳磨牙，中龋或深龋，随机分为化学法去龋组和机械法去龋组，每组20个牙，去龋前后使用无菌挖匙对龋坏牙本质进行取样，分别在4种不同的培养基上进行厌氧培养和计数。结果：两种方法去龋后，除机械法去龋组放线菌外，两种方法其他细菌数显著减少，有统计学意义（P〈0．05），化学法去龋组比机械法去龋组的总菌数量减少更显著（p〈0．05）。结论：化学去龋法比机械去龋法清除乳牙龋坏细菌效果好。     

Comparison of the efficacy of chemomechanical caries removal (Carisolv) with that of conventional excavation in reducing the cariogenic flora

OBJECTIVES: The usage of minimally invasive procedures and attention to patient comfort are of great importance, especially for dental treatment in small children. This has led to the development of chemomechanical methods for caries removal. The aim of this study was to compare the efficacy of chemomechanical caries removal with that of conventional excavation in reducing the count of the cariogenic flora. DESIGN AND SETTING: Subjects for this study were chosen from children admitted to dental clinic for restorative procedures under general anaesthesia. SAMPLES AND METHODS: Twenty-one children (mean age 43.5 +/- 12.0 months) with early childhood caries were included in this study. Two primary teeth with comparable degrees of carious destruction were chosen in each child (n = 42) for caries removal with Carisolv' or by means of rotary instruments. Samples from carious dentine were taken with a sterile scraping instrument, then all softened dentine was removed and a second sample was taken. All samples (n = 84) were serially diluted and plated on two different nutrient agar plates. RESULTS: After 24 h of incubation, colony forming units were determined for total bacterial counts and lactobacilli. Twelve per cent of the samples from carious dentine contained more than 10(6) bacteria, 23.8% contained more than 10(5) lactobacilli. Both methods of caries removal produced a statistically significant reduction in the bacterial counts (P = 0.0001). In at least 90.5% of the samples taken after the removal, the total bacterial count was below 10(2), and in 95.2% lactobacilli fell below 10(2). CONCLUSION: These results indicate that the efficacy of chemomechanical removal of carious dentine in children by means of Carisolv' is comparable to the results obtained by conventional methods, and thus might serve as a suitable alternative.