and fracture. In the abfraction theory of causation, tensile forces resulting from cuspal flexure in response to heavy occlusal loading are concentrated on the cervical areas of the tooth. Micro-cracks then develop when the bonds between hydroxyapatite crystals in enamel and dentin break. Further abrasion and corrosion can develop. Within this framework, occlusal adjustment is the proposed treatment approach. However, this theory is not well supported clinically or nonclinically. An investigation into the microwear aspects of NCCLs was aimed at understanding their causation more clearly, with implications for treatment planning.
Table 1.—Summary of Wear Characteristics of Noncarious Cervical Lesions (NCCLs)
Methods.—The 24 extracted teeth had large cervical lesions. Polyvinylsiloxane impression material was used to make negative replicas of these lesions, which were then examined under the scanning electron microscope (SEM).
needed to verify the abfraction hypothesis. The furrows running horizontally in these specimens varied in width, raising the possibility that narrower furrows may coalesce to form wider ones. A separate study is aimed at developing a classification system for NCCLs based on morphological form and relating the categories to etiology. Until further evidence is found to support abfraction, occlusal adjustment to manage NCCLs is not advisable.
Results.—All of the NCCLs occurred on the buccal surfaces of the teeth and extended from the CEJ to the root surface. They varied in appearance but all had evidence of abrasion and/or corrosion. SEM analysis showed horizontal scratching (abrasion) and smooth surfaces (corrosion). When the two patterns were both present, the scratch marks were less prominent. Eighteen of the 24 teeth (75%) had evidence of both abrasion and corrosion (Table 1). Over 50% had horizontal furrows whose widths varied from 5 to 250 mm. Some extended mesiodistally along nearly the entire length of the NCCLs. These furrows were generally smooth with minor horizontal scratch marks. Discussion.—The current study details the appearance of various NCCLs, attributing the patterns seen to abrasion and/or corrosion. Evidence of each process was found, with most lesions having both present. However, the extensive crack networks that would support abfraction as the causative process were not seen. Some researchers believe these only occur on cervical enamel. More convincing evidence is
Both abrasion and corrosion Abrasion only Corrosion only Total
Number of teeth
Per cent (%)
18 1 5 24
75.0 4.2 20.8 100.0
(Courtesy of Nguyen C, Ranjitkar S, Kaidonis JA, et al: A qualitative assessment of non-carious cervical lesions in extracted human teeth. Austral Dent J 53:46-51, 2008. Reprinted with permission from the Australian Dental Journal.)
Clinical Significance.—Results of this study fail to support the abfraction theory for noncarious cervical lesions, instead suggesting abrasion and corrosion as the culprits. Treatment with occlusal adjustment seems misdirected at this point.
Nguyen C, Ranjitkar S, Kaidonis JA, et al: A qualitative assessment of non-carious cervical lesions in extracted human teeth. Austral Dent J 53:46-51, 2008 Reprints available from S Ranjitkar, School of Dentistry, The Univ of Adelaide, Adelaide, South Australia 5005; e-mail: [email protected]
Oral Medicine Amalgam removal or not Background.—Safety concerns related to the mercury content of dental amalgam have been discussed for many years, even while it is still used as filling material. Some persons with amalgam fillings blame them for chronic, subjective, nonspecific health problems. Some of the symptoms of these ‘‘amalgam patients’’ correspond to the major toxic effects known to accompany mercury exposure. In
1995 about 1500 persons claiming health injury from amalgam filed suit against the Degussa company, which makes amalgam in Germany. A portion of the settlement funds has been used to sponsor research into the amalgam situation. The effectiveness of three treatment strategies for amalgam patients in reducing health complaints unexplained by other medical or psychological conditions was investigated.
Methods.—The 90 individuals were randomly assigned to removal of the dental amalgam only, removal plus a ‘‘biological detoxification’’ therapy using high doses of vitamins and trace elements, or participation in a health promotion program without removing the amalgam. Patients’ main complaints were measured over a period of 12 months. In addition, the study looked secondarily at total symptom scores after 18 months, quality of life, psychic symptoms and signs, and blood and urine mercury levels after 12 and 18 months. Results.—The ‘‘main complaint’’ sum score fell an average of 3.5 points in both of the groups that had amalgam removed and by 2.5 points among the health promotion program participants. The secondary outcomes showed no differences between the three groups. Descriptive analysis revealed continuous improvement through 18 months. Except for total mercury in the erythrocytes, analysis of the blood and urine samples showed significantly lower mercury levels after the amalgam was removed compared to the group with amalgam retention. No significant change in the concentrations of inorganic mercury in erythrocytes and plasma, the total mercury in plasma, or the urine parameters occurred in any of the groups between the 12- and 18-month measurements. Fortythree persons across the three groups reported 73 new complaints, of which 16% were gastrointestinal, 15% were arthralgia/back pain related, 11% were dental problems caused by the replacement of restorations after the amalgam was
removed, 10% were skin diseases, 7% were infections, 7% were sensory disorders, and 34% fell into the ‘‘other’’ category. Discussion.—Removing the dental amalgam from these patients was accompanied by fewer subjective complaints and less mental stress similar to the reduction in patients whose amalgam remained. The improvements noted were clinically relevant and continued for the 18 months of the study. Amalgam removal is not the only effective treatment for amalgam patients.
Clinical Significance.—What effect does the presence of amalgam dental restorations have on the host? The question persists and remains definitively unresolved. In this study of three groups, removal of amalgam restorations, removal with ‘‘detoxification’’ therapy, and nonremoval combined with a health promotion program were compared.
Melchart D, Vogt S, Ko¨hler W, et al: Treatment of health complaints attributed to amalgam. J Dent Res 87:349-353, 2008 Reprints available from D Melchart, Kaiserstr 9, D-80801 Munich, Germany; e-mail: [email protected]
Pain and Pain Control Hypnosis to relieve persistent idiopathic orofacial pain Background.—Patients may come for the relief of pain with complex, diffuse symptoms but no radiologic or clinical pathologic findings. These individuals describe their pain as intolerable and diminishing their quality of life. They have often tried various types of treatments without benefit. Their mental health exerts a significant impact on maintaining or aggravating chronic pain, so cognitivebehavioral interventions can prove effective. Hypnotic analgesia treatments can significantly reduce perceived pain compared to no treatment, but evidence is lacking concerning the specific effect of hypnosis on persistent idiopathic orofacial pain (PIOP). Whether hypnosis for patients suffering from PIOP can improve their pain, use of analgesics, sleep quality, health-related quality of life, and psychological symptoms was tested. Also investigated was the relationship between hypnotic susceptibility, pain coping strategies, and primary outcome measures. Methods.—The 44 patients had PIOP for over 6 months without pathologic results on clinical and radiologic tests.
The criteria of The International Headache Society were used, including facial pain present each day, all or most of the day for at least 1 month; pain that is deep, poorly localized, moderate or severe, but not unbearable; pain confined at onset to a single side of the head; and no paroxysms, trigger areas, autonomic symptoms, sensory loss, or other physical signs. The patients were randomly assigned to receive hypnotic treatment or relaxation only. The hypnotic intervention group underwent progressive relaxation leading to a trance state when it was suggested that the patient’s coping mechanisms for psychologic problems and stress management efforts were improving. The control group underwent relaxation and visualization without these suggestions. All patients completed a diary of selfreported pain status using a visual analogue scale (VAS) ranging from 0 to 10. They also filled in a McGill pain questionnaire at baseline and after the final treatment. They reported all use of analgesics and rated their sleep quality on a scale from 0 to 6. A symptom checklist was used to record psychologic symptoms, listing 60 items to measure