Interleukins in gingival crevicular fluid in patients with definitive full-coverage restorations

The objective of this study was to determine interleukin (IL)-1α and IL-8 levels in the gingival crevicular fluid (GCF) of patients with different levels of crown margin placements. Samples of GCF were obtained from 12 study participants with definitive full-coverage restorations with supragingival or equigingival crown margin placements. The periodontal status of the volunteers ranged from healthy to generalized severe periodontitis. Pocket depth and bleeding on probing were assessed at the clinical examination, and interleukin concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Analysis of variance (ANOVA) was used to statistically compare interleukin concentrations between the control, supragingival, and equigingival GCF samples. Compared to controls (60.4 ± 8.9 pg/mL), the average IL-1α concentration in the GCF samples surrounding the supragingival margins was 53.8 ± 9.7 pg/mL and was 110.5 ± 23.3 pg/mL in the equigingival margins. Compared to controls (59.0 ± 14.1 pg/mL), the average IL-8 concentration in the supragingival margins was 46.9 ± 9.7 pg/mL and was 131.4 ± 27.5 pg/mL in the equigingival margins. The trend of higher levels of interleukins in GCF corresponding to equigingival margins was consistent, as was the trend of lower concentrations in supragingival margins compared to the controls; however, statistical significance was not achieved because of the wide biological variation within and between patients. In conclusion, differences in GCF IL-1α and IL-8 concentrations were observed when comparing fixed crown restorations with equigingival and supragingival margins. Gingival inflammation may be dependent on the periodontal condition in addition to restoration or margin placement.

Plaque formation and marginal gingivitis associated with restorative materials

The presence of restorative materials on tooth surfaces is perceived to be a contributing factor to periodontal disease. This observation is a result of the increased accumulation of plaque on restorations adjacent to the gingiva, which may lead to gingivitis. Plaque is believed to adhere better to restorations than to enamel. This may be due to the surface characteristics of restorative materials such as surface roughness and surface-free energy inherent in the materials. This article reviews the experimental studies of plaque formation on different restorative materials. In addition, clinical studies analyzing and comparing restorative materials and the consequent formation of gingivitis are reviewed. While in vitro and in vivo studies show variations in plaque formation among restorative materials and enamel, clinical studies demonstrate that the progression of gingivitis can be prevented if patients maintain adequate oral hygiene and home care. Therefore, instructing the patient to maintain proper oral hygiene and home care is more important than the choice of restorative material.

Plaque formation and marginal gingivitis associated with restorative materials

The presence of restorative materials on tooth surfaces is perceived to be a contributing factor to periodontal disease. This observation is a result of the increased accumulation of plaque on restorations adjacent to the gingiva, which may lead to gingivitis. Plaque is believed to adhere better to restorations than to enamel. This may be due to the surface characteristics of restorative materials such as surface roughness and surface-free energy inherent in the materials. This article reviews the experimental studies of plaque formation on different restorative materials. In addition, clinical studies analyzing and comparing restorative materials and the consequent formation of gingivitis are reviewed. While in vitro and in vivo studies show variations in plaque formation among restorative materials and enamel, clinical studies demonstrate that the progression of gingivitis can be prevented if patients maintain adequate oral hygiene and home care. Therefore, instructing the patient to maintain proper oral hygiene and home care is more important than the choice of restorative material.

Toothbrush abrasions and noncarious cervical lesions: evolving concepts

Toothbrush abrasion at the cervical areas of teeth is generally thought to be a result of frequent or forceful toothbrushing, faulty or vigorous technique, filament stiffness or design, dominant hand dexterity, or abrasive dentifrices. However, a review of the evidence-based literature cannot conclusively establish any one factor as the primary etiology of cervical abrasions because of inherent methodological limitations and conflicting results. Rather, a variety of factors related to toothbrushing may act in concert with dental erosion and, possibly, occlusal loading in the creation of noncarious cervical lesions. Individual variation also may make some individuals more susceptible to development and may modify the progression of those lesions. Individual variations may involve oral and dental anatomy, periodontal status or phenotype, and periodontal disease history and treatment. Further research is needed to clearly assess the interaction of all those factors in the development of cervical lesions. Therefore, awareness of a multifactorial etiology in noncarious cervical lesions may help the clinician to formulate an appropriate treatment plan for the patient.

Wedged cervical lesions produced by toothbrushing

PURPOSE

To compare the morphology of experimentally induced cervical toothbrush abrasion lesions to teeth demonstrating non-carious cervical lesions in vivo.

METHODS

Eighteen premolars extracted for orthodontic reasons were each subjected to 80 hours (1.4 million strokes) of horizontal brushing in a custom fabricated toothbrushing machine. Toothpaste slurry was applied continuously and specimens were subjected to 300 gms of toothbrushing force. Denture base resin was used to simulate gingival recession of 1 mm and a sulcus width of 0.1 mm. Cervical abrasions were analyzed by optical and scanning electron microscopy and classified as either V-shape/wedged vs. U-shape/rounded lesions. When lesions exhibited both shapes, they were classified as mixed. Shapes of experimentally induced lesions then were compared to naturally occurring ones found on extracted premolars. RESULTSts: Experimentally induced toothbrush abrasion duplicated the classical clinical shapes. Half (9/18) of the experimentally induced toothbrush abrasions exhibited wedged lesions, 28% (5/18) showed a mixed wedged/rounded lesion, and 22% (4/18) showed rounded lesions. Serial photography showed progression of the morphology of the lesions. Toothbrush abrasion apparently begins apical to the cemento-enamel junction, progresses to dentin, and then undermines enamel with loss of the original cemento-enamel junction. Wedged lesions may appear with the apex oriented coronal or apical, or may be symmetrical.

Erupted complex odontoma: a case report and literature review

A case involving a 17-year-old girl with a large erupted odontoma associated with a deeply impacted mandibular molar is reported. The molar, which previously had been displaced to the border of the mandible, erupted successfully three years after surgical removal of the odontoma. A review of the literature presents guidelines for treating similar cases.

Effects of occlusal load on cervical lesions

Toothbrush abrasion has been considered to cause cervical lesions. However, some investigators have proposed that occlusal loading factors direct tensile stresses at the cervical area, resulting in wedge-shaped abfraction defects. The purpose of this study is to investigate the role of axial and non-axial load on the development of cervical lesions. Matched paired premolars, extracted for orthodontic purposes, were used in a custom-fabricated toothbrushing apparatus. A periodontal sulcus width of 0b1 mm with 1 mm gingival recession was simulated with denture base resin. In phase 1, eight matched premolar pairs were subjected to 80 h (1b4 million strokes) of brushing and 300 g of toothbrush force. Toothpaste slurry was applied continuously through the toothbrush. One specimen in each pair was subjected to 250 h and 45 kg of continuous axial load, while the other unloaded tooth served as a negative control. In phase 2, 10 matched premolar pairs were subjected to the same conditions; however, the experimental teeth were subjected to 250 h and 45 kg of intermittent non-axial load, directed at a 45 degrees angle to the buccal cusp. Rubber impressions were made of the cervical lesions, then trimmed, weighed, and compared to determine the amount of tooth material lost. When teeth were loaded axially, there was significantly less tooth material loss (P < 0b02); however, when teeth were loaded non-axially, there was no significant difference (P =0b80) when compared with controls. Optical and scanning electron microscopy did not reveal any significant differences in the morphology between pairs. Our data suggest that the application of occlusal load may not necessarily play a significant role in the progression of cervical tooth wear commonly referred to as abfraction.

An assessment of stress analyses in the theory of abfraction

Wedged-shaped lesions at the cemento-enamel junction of teeth have been attributed primarily to biomechanical loading forces that cause flexure and failure of enamel and dentin. This theory, termed abfraction, remains controversial. This review examined studies on mechanical properties of enamel and dentin and studies on bite forces and mastication as background information. Abfraction is based principally on a few early finite element analysis and photoelastic models showing stress concentration at the dental cervical area without actually showing enamel and dentin fracture. However, a review of more recent dental stress analyses has been contradictory. Particularly, analyses of the periodontal ligament and alveolar bone, not modeled in previous studies, have shown that those structures may dissipate occlusal loading forces from the cervical areas. In addition, some models may not fully represent intricate dental anatomy and complex occlusal function. Therefore, the key basis of the abfraction theory may be flawed.

Noncarious cervical lesions and abfractions: a re-evaluation

BACKGROUND

The concept of abfraction is controversial. The authors present the fundamental basis of abfraction and review studies that describe the condition.

TYPES OF STUDIES REVIEWED

The authors used data on masticatory forces, enamel and dentin properties, as well as stress studies related to abfraction, for background information. They also analyzed the genesis of the abfraction theory, experimental evidence, case presentations, clinical investigations and restorative studies.

RESULTS

The theory of abfraction is based primarily on engineering analyses that demonstrate theoretical stress concentration at the cervical areas of teeth. While some recent stress studies support earlier findings, others have provided significant deviating information. Few controlled studies exist that demonstrate the relationship between occlusal loading and abfraction lesions. The role of occlusal loading in noncarious cervical lesions (as shown by clinical data) appears to be part of a multifactorial event that may not necessarily follow the proposed classic abfraction mechanism, and other mechanisms or factors may explain cervical restoration failure just as well.

CLINICAL IMPLICATIONS

There is little direct evidence supporting the theory of abfraction as the primary factor in the formation of noncarious cervical lesions. Controlled clinical trials are necessary to elucidate more fully the etiology of those lesions.

Tooth wear: attrition, erosion, and abrasion

Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification acts through a distinct process that is associated with unique clinical characteristics. Accurate prevalence data for each classification are not available since indices do not necessarily measure one specific etiology, or the study populations may be too diverse in age and characteristics. The treatment of teeth in each classification will depend on identifying the factors associated with each etiology. Some cases may require specific restorative procedures, while others will not require treatment. A review of the literature points to the interaction of the three entities in the initiation and progression of lesions that may act synchronously or sequentially, synergistically or additively, or in conjunction with other entities to mask the true nature of tooth wear, which appears to be multifactorial.

Toothbrushing and gingival recession

AIM

To review the hypothesis that toothbrushing leads to gingival recession. Gingival recession develops due to anatomical and pathological factors. The prevalence of recession is dependent on the age and characteristic of the population because it usually presents in individuals with periodontal disease or those who practise zealous or improper oral hygiene methods. Gingival trauma and gingival abrasion from toothbrushing is thought to progress directly to gingival recession. Case studies documenting recession from toothbrush trauma are speculative. Short-term studies suggest that gingival trauma and gingival abrasion may result from toothbrushing, but the direct relationship between traumatic home care and gingival recession is inconclusive. Long-term studies remain elusive or do not support the development of recession following toothbrushing. Nevertheless, tooth abrasion may be an integral part in the aetiology of recession. Toothbrush abrasion also may cause wear at the cemento-enamel junction resulting in the destruction of the supporting periodontium leading to recession.