Micro-computed tomography analysis of post space preparation in root canals filled with carrier-based thermoplasticized gutta-percha.

AIM: To determine whether post space preparation deviated from the root canal preparation in canals filled with Thermafil, GuttaCore or warm vertically compacted gutta-percha. METHODOLOGY: Forty-two extracted human permanent maxillary lateral incisors were decoronated, and their root canals instrumented using a standardized protocol. Samples were divided into three groups and filled with Thermafil (Dentsply Tulsa Dental Specialties, Johnson City, TN, USA), GuttaCore (Dentsply Tulsa Dental Specialties) or warm vertically compacted gutta-percha, before post space preparation was performed with a GT Post drill (Dentsply Tulsa Dental Specialties). Teeth were scanned using micro-computed tomography after root filling and again after post space preparation. Scans were examined for number of samples with post space deviation, linear deviation of post space preparation and minimum root thickness before and after post space preparation. Parametric data were analysed with one-way analysis of variance (anova) or one-tailed paired Student's t-tests, whilst nonparametric data were analysed with Fisher's exact test. RESULTS: Deviation occurred in eight of forty-two teeth (19%), seven of fourteen from the Thermafil group (50%), one of fourteen from the GuttaCore group (7%), and none from the gutta-percha group. Deviation occurred significantly more often in the Thermafil group than in each of the other two groups (P < 0.05). Linear deviation of post space preparation was greater in the Thermafil group than in both of the other groups and was significantly greater than that of the gutta-percha group (P < 0.05). Minimum root thickness before post space preparation was significantly greater than it was after post space preparation for all groups (P < 0.01). CONCLUSIONS: The differences between the Thermafil, GuttaCore and gutta-percha groups in the number of samples with post space deviation and in linear deviation of post space preparation were associated with the presence or absence of a carrier as well as the different carrier materials.

HyFlex nickel-titanium rotary instruments after clinical use: metallurgical properties.

AIM: To analyse the type and location of defects in HyFlex CM instruments after clinical use in a graduate endodontic programme and to examine the impact of clinical use on their metallurgical properties. METHODOLOGY: A total of 468 HyFlex CM instruments discarded from a graduate endodontic programme were collected after use in three teeth. The incidence and type of instrument defects were analysed. The lateral surfaces of the defect instruments were examined by scanning electron microscopy. New and clinically used instruments were examined by differential scanning calorimetry (DSC) and x-ray diffraction (XRD). Vickers hardness was measured with a 200-g load near the flutes for new and clinically used axially sectioned instruments. Data were analysed using one-way anova or Tukey's multiple comparison test. RESULTS: Of the 468 HyFlex instruments collected, no fractures were observed and 16 (3.4%) revealed deformation. Of all the unwound instruments, size 20, .04 taper unwound the most often (n = 5) followed by size 25, .08 taper (n = 4). The trend of DSC plots of new instruments and clinically used (with and without defects) instruments groups were very similar. The DSC analyses showed that HyFlex instruments had an austenite transformation completion or austenite-finish (Af ) temperature exceeding 37 °C. The Af temperatures of HyFlex instruments (with or without defects) after multiple clinical use were much lower than in new instruments (P < 0.05). The enthalpy values for the transformation from martensitic to austenitic on deformed instruments were smaller than in the new instruments at the tip region (P < 0.05). XRD results showed that NiTi instruments had austenite and martensite structure on both new and used HyFlex instruments at room temperature. No significant difference in microhardness was detected amongst new and used instruments (with and without defects). CONCLUSIONS: The risk of HyFlex instruments fracture in the canal is very low when instruments are discarded after three cases of clinical use. New HyFlex instruments were a mixture of martensite and austenite structure at body temperature. Multiple clinical use caused significant changes in the microstructural properties of HyFlex instruments. Smaller instruments should be considered as single-use.

Treatment needs (TN) and practical remedies for halitosis.

Dental practitioners have traditionally neglected halitosis despite its high priority for the public, but practitioners' interest in halitosis has recently increased. Although oral pathologic or physiologic halitosis is easily reduced by a suitable treatment based on the treatment needs, systemic and psychological conditions sometimes confuse practitioners. Since a halitophobic patient never agrees with the result that his/her oral malodour has been reduced or eliminated after treatment, this may cause a dilemma for practitioners. Generally, halitosis patients, even genuine ones, have different psychological characteristics concerning their own breath than other individuals. Adverse psychological aspects of these patients are often promoted by the practitioner's mismanagement. Treatment Needs (TN) were, therefore, established to prevent practitioners' mismanagement of halitosis patients. By following these TN, patients can receive proper treatments for halitosis. However, to choose proper treatment measures, practitioners must refer to articles published in peer-reviewed journals, then use critical thinking to judge whether a product is effective in reducing oral malodour. Although it is challenging for dental practitioners to deal with patients with psychological conditions such as pseudo-halitosis or halitophobia, if appropriate treatments are administered accurately the practitioner does not risk mismanagement.

Tongue brushing and mouth rinsing as basic treatment measures for halitosis.

Tongue brushing and mouth rinsing are basic treatment measures for halitosis, and as such are categorised as treatment needs (TN)-1. Although TN-1 is used for treatment of physiologic halitosis treatment, pseudo-, extra oral pathologic or halitophobic patients must also be managed with TN-1 as well as other treatments. Since the origin of physiological halitosis is mainly the dorso-posterior region of the tongue, tongue cleaning is more effective than mouth rinsing. However, practitioners should always instruct their patients on how to brush their tongues to prevent harmful effects. Another approach using a chlorhexidine mouthwash is most effective in reducing oral malodour. However, chlorhexidine should not be used routinely; therefore, zinc-containing mouthwashes have been recommended for use. People can also use chewing gum to reduce oral malodour. Surprisingly, however, it has been noted that sugarless chewing gum increased methyl mercaptan, one of the principal components of oral malodour. Mint did not reduce the concentration of methyl mercaptan either, although these products are widely used for their ability to mask oral malodour. There is a need for the development of a novel food or chewing gum that could considerably reduce VSC levels in mouth air to complement TN-1.

Examination, classification, and treatment of halitosis; clinical perspectives.

Patients with halitosis may seek treatment from dental clinicians for their perceived oral malodour. In this article, an examination protocol, classification system and treatment needs for such patients are outlined. Physiologic halitosis, oral pathologic halitosis and pseudo-halitosis would be in the treatment realm of dental practitioners. Management may include periodontal or restorative treatment or both, as well as simple treatment measures such as instruction in oral hygiene, tongue cleaning and mouth rinsing. Psychosomatic halitosis is more difficult to diagnose and manage, and patients with this condition are often mismanaged in that they receive only treatments for genuine halitosis, even though they do not have oral malodour. A classification system can be used to identify patients with halitophobia. Additionally, a questionnaire can be used to assess the psychological condition of patients claiming to have halitosis, which enables the clinician to identify patients with psychosomatic halitosis. In understanding the different types of halitosis and the corresponding treatment needs, the dental clinician can better manage patients with this condition.

Clinical application of a questionnaire for diagnosis and treatment of halitosis.

To treat halitosis, clinicians must examine the psychologic condition of a patient as well as the disease history and plausible causes of oral malodor, such as periodontal disease. However, it is not easy for a practitioner to carry out a psychologic examination other than the normal inquiry concerning oral malodor itself. Hence, a questionnaire that appears to be a normal inquiry, rather than one containing psychologic questions, was composed to survey the causes of halitosis and psychosomatic tendencies.

Clinical dilemmas posed by patients with psychosomatic halitosis.

Patients affected by psychosomatic halitosis never wish to visit a psychologic specialist, because they cannot recognize their own psychosomatic condition. They also never doubt that they have offensive oral malodor. Other people's behavior, such as covering the nose or averting the face, is interpreted by these patients as an indication that their breath is offensive, and these behaviors or attitudes reinforce their belief that they have a strong oral malodor. To clarify whether the patient's perception of another individual's attitude is affected by his or her delusion, this article is focused on the relationship between the behavior toward oral malodor and the psychologic profiles of patients with psychosomatic halitosis. If a patient expects simple avoidance behavior from other individuals, the development of psychosomatic halitosis may be accelerated, as it becomes a self-fulfilling prophecy. Individuals who are concerned with their own oral malodor but exhibit no oral malodor may have latent psychosomatic tendencies and may be mentally immature. A protocol for referring a patient to a psychologic specialist is presented.

Genuine halitosis, pseudo-halitosis, and halitophobia: classification, diagnosis, and treatment.

Although tongue brushing and appropriate mouthrinses are both important and basic treatment measures for halitosis, other dental treatments are sometimes required. The treatment of genuine halitosis caused by oral conditions is not complex. In addition to genuine halitosis patients, psychosomatic halitosis patients also visit dental practitioners. Although psychosomatic halitosis is out of the treatment realm of dental practitioners, patients with this condition will still seek help from a dental practitioner. They often only receive treatment for genuine halitosis without referral to a psychological specialist. If these psychosomatic halitosis patients are incorrectly managed, the psychological condition might become worse than before the visit. To avoid the mismanagement of halitosis patients, classifications of halitosis patients have been established. Genuine halitosis was subclassified as physiologic halitosis and pathologic halitosis. Pathologic halitosis was further categorized to oral pathologic halitosis and extraoral pathologic halitosis. Both pseudo-halitosis and halitophobia patients complain of the existence of halitosis, which is not offensive. Pseudo-halitosis cannot be treated by dental practitioners, and halitophobia patients must be referred to psychological specialists. Clinicians need to examine the psychological condition of halitosis patients at the initial patient visit. A questionnaire prepared for the clinic at the University of British Columbia was found to be advantageous for this purpose.

Gas chromatographic method for trapping and detection of volatile organic compounds from human mouth air.

The present investigation describes a convenient method for collection and analysis of volatile organic compounds from 25 ml mouth air samples. Tenax-GC trapping devices coated with Teflon are used to adsorb and concentrate volatile organic compounds in mouth air at -20 degrees C, which are then thermally desorbed at 140 degrees C. Gas chromatography (GC) analyses are performed using an aluminum column coated with Teflon and packed with 2% poly-MPE on 80/100 mesh Tenax-GC, and employing a flame ionization detector. This procedure allows for amplification of peak heights and detection of compounds that may otherwise escape direct analysis. Of the six prominent peaks detected, identification based on retention times indicates the presence of methanol, acetaldehyde, ethanol and acetone. Volatiles collected using this procedure can be maintained at -20 degrees C for up to 48 hours before analysis. The compact sample tubes allow the system to be easily portable, particularly suitable for sampling breath of persons with localized oral or systemic diseases at locations away from the laboratory. The superiority of this method is that relatively small samples are required for analysis, unlike previously published methods which are based on collection of large volumes of expired air in plastic bags.

Dens evaginatus from an orthodontic perspective: report of several clinical cases and review of the literature.

The anomaly of dens evaginatus manifests itself as an innocuous-looking tubercle of enamel on the occlusal surface of a premolar tooth. Problems can arise when the tubercle is either worn, ground, or fractured off, resulting in pulpal exposure and possible loss of vitality of the tooth. Orthodontists should be particularly aware of this dental anomaly, which occurs in at least 2% of the Asian and Native Indian population. Premolar extraction cases should be planned to include extraction of the anomalous premolars instead of the normal ones. In addition, the orthodontist should be wary of occlusal changes during treatment or occlusal equilibration that might jeopardize the vitality of teeth with dens evaginatus. Pulp-capping or partial pulpotomy has been postulated as the most reliable form of treatment to prevent loss of vitality of the affected teeth and to allow continued root maturation where necessary.

Dens evaginatus: review of the literature and report of several clinical cases.

Dens evaginatus (DE) presents as an innocuous looking tubercle of enamel on the occlusal surface of a tooth, most commonly a bicuspid. Problems can arise when the tubercle is either worn, ground, or fractured off, resulting in pulpal exposure and possible loss of vitality of the tooth. Dentists who perform orthodontic treatment should be aware of this dental anomaly, which occurs in at least two per cent of the Asian and Native Indian populations. Bicuspid extraction cases should involve the extraction of the anomalous premolars rather than the normal ones. In addition, the dentist should be mindful of occlusal changes that may occur during treatment or occlusal equilibration, both of which can jeopardize the vitality of teeth with DE. Pulp capping or partial pulpotomy has been postulated to be one of the most reliable forms of vital tooth treatment when pulp exposure is encountered following the sterile removal of the tubercle. When pulp exposure is not encountered, preventive resin composite sealing of the dentin or class I amalgam cavity preparation seems to be the treatment of choice.