Occlusal stress is involved in the formation of non-carious cervical lesions. A systematic review of abfraction

PURPOSE

This systematic review on abfraction studied whether stress is a mechanism in the formation of non-carious cervical lesions (NCCLs).

METHODS

A literature search was performed on three electronic databases (PubMed, ISI Web of Science, and EMBASE) using the keyword "abfraction" in publications published in English. The inclusion criteria were clinical and laboratory studies that investigated the role of abfraction in NCCLs. The title and abstract of the identified publications were screened by two investigators independently. Reviews, case reports, and irrelevant papers were excluded. Full text of the remaining publications were retrieved. A manual search was performed on the bibliographies of the selected publications to identify additional relevant publications for review.

RESULTS

A total of 372 publications were identified, and 165 duplicated publications and 166 irrelevant publications were excluded. From the bibliographies of the remaining 41 publications, 28 relevant publications were found. Therefore, 69 publications (31 clinical studies and 38 laboratory studies) were included in this review and the majority (56/69, 81%) found an association between occlusal stress and NCCLs. Although no clinical study demonstrated that NCCL was caused by stress alone, 23 studies reported that stress or occlusal factors were associated with NCCLs. Of the 38 laboratory studies, 24 that used finite element analysis found that stress was concentrated at the cervical region of the tooth. Nine laboratory studies suggested that stress was a mechanism for NCCLs, whereas five studies reported the opposite. In conclusion, current literature supported an association between occlusal stress and NCCLs.

CLINICAL SIGNIFICANCE

This systematic review of abfraction found the majority of studies reported an association between occlusal stress and non-carious cervical lesions.

Inhibition of Notch Signaling During Mouse Incisor Renewal Leads to Enamel Defects

The continuously growing rodent incisor is an emerging model for the study of renewal of mineralized tissues by adult stem cells. Although the Bmp, Fgf, Shh, and Wnt pathways have been studied in this organ previously, relatively little is known about the role of Notch signaling during incisor renewal. Notch signaling components are expressed in enamel-forming ameloblasts and the underlying stratum intermedium (SI), which suggested distinct roles in incisor renewal and enamel mineralization. Here, we injected adult mice with inhibitory antibodies against several components of the Notch pathway. This blockade led to defects in the interaction between ameloblasts and the SI cells, which ultimately affected enamel formation. Furthermore, Notch signaling inhibition led to the downregulation of desmosome-specific proteins such as PERP and desmoplakin, consistent with the importance of desmosomes in the integrity of ameloblast-SI attachment and enamel formation. Together, our data demonstrate that Notch signaling is critical for proper enamel formation during incisor renewal, in part by regulating desmosome-specific components, and that the mouse incisor provides a model system to dissect Jag-Notch signaling mechanisms in the context of mineralized tissue renewal.

Evaluation of internet search trends of some common oral problems, 2004 to 2014

OBJECTIVE

Internet search trend volumes can provide free, fast and pertinent information about peoples' online interests. No study has yet been conducted on internet search trends in dentistry. This study aims to investigate ten years' data on internet search volumes regarding some oral problems: "toothache", "tooth decay", "gum disease", "wisdom teeth" and "oral cancer". The study also aims to investigate the most common geographic search locations and to examine related searches.

RESEARCH DESIGN

Worldwide intermet search trend data over a period of 532 weeks (4 January 2004 and 15 March 2014) retrieved from the Google Trends web site was interrogated for each search term to identify search trends, regional interests, and related searches.

RESULTS

The search volumes for the terms "toothache "and "wisdom teeth" increased over the decade while "tooth decay", "gum disease", and "oral cancer" showed slight changes. Each term was most commonly searched in different counties: "toothache", Philippines; "tooth decay", Singapore; "Gum Disease", Ireland; "Wisdom Teeth", United States; and "Oral cancer", India. Related searches were mainly focused on symptoms and remedies of these problems.

CONCLUSIONS

Regional and time-related variations in search volumes may provide dental professionals with readily- and freely-available pertinent information on populations' internet searches regarding dental complaints.

Application of the community oral health indicator by non-dental personnel and its contribution to oral healthcare

Objective

To validate the Community Oral Health Indicator-COHI by non-dental personnel.

Methods

Risk assessment is an essential component in the decision-making process. Therefore, the COHI, an instrument to evaluate population oral health situation in a simple manner, was created. Community Health Agents (CHA) were trained to use the COHI (variables as number of teeth, presence of cavities, residual dental roots, oral lesions, etc.), while dentists for the COHI and DMFT. 60 individuals were examined, by CHA and DS, with these indicators in order to validate the use of COHI by non-dental personnel.

Results

Dental and soft tissues problems were well spread among those individuals. People with and without soft tissue damage, as well as with and without use and/or need for prostheses were found in the sample, proving it to be a heterogeneous population for the evaluated factors and representing the real population. The results of examinations performed by dentists using the COHI and DMF-T/dmf-t presented strong agreement when comparing the two instruments. When COHI and DMFT were compared, the results showed a concordance of 0.86 for the number of present teeth, and 0.85 for the number of residual roots. Likewise, when analyzing the data comparing the use of the COHI by DS and CHA a high agreement level, specificity and sensitivity was found.

Conclusion

The COHI has shown to be useful for detecting problems in oral health. Therefore, COHI may be used, after training, by non-dental personnel, contributing to the planning and organization of the community dental assistance.

Quantitative EDXRF analysis of Ca, K, Mn and Na in normal and pathological adult-human teeth

This work relates to the measurement of calcium, potassium, manganese and sodium levels in adult-human teeth from female and male patients and normal subjects. Energy dispersive X-ray fluorescence (EDXRF) technique was used for the measurements. Pathological and non-pathological adult-human teeth samples were collected from one male human patient and one female human patient who attended the dental clinic. The standard addition method was used to determine concentrations. Experimental results are presented and discussed in this work.

[Clinical experience of tracheal intubation using Trachlight in patients with unstable dentition]

BACKGROUND

Trachlight is a light-tipped stylet designed to guide tracheal intubation. It obviates the need for direct laryngoscopy and is reported to be particularly useful for managing difficult tracheal intubation. Its clinical application, however, is not limited to difficult airway management.

METHODS

Here we report our experience of the use of Trachlight in 64 adult patients who were at risk of dental injury during direct laryngoscopy because of unstable teeth around the incisors or severe alveolar disease.

RESULTS

Of 64 patients (33 men and 31 women) aged between 30 and 85, the trachea was successfully intubated using Trachlight without dental damage in 63 patients. In 1 patient, a tracheal tube was smoothly placed, but a tooth was injured after the removal of the stylet. No other complications associated with the use of Trachlight were noted.

CONCLUSIONS

Our experience suggests that Trachlight can be a helpful tool for intubation in patients having dental problems. Because of the blind nature of the technique, but preexisting lesions of the larynx and vocal cords might be overlooked in intubation using Trachlight. Further investigation is warranted to recommend Trachlight as a intubation technique of choice in patients with unstable dentition.

Limiting factors in orthodontic treatment: 2. The biological limitations of orthodontic treatment

Owing to a shortage in the orthodontic workforce in the United Kingdom, general dental practitioners carry out orthodontic treatment in selected cases. Orthodontic treatment may not always be successful due to various factors. Some of these limiting factors are related to the practitioner, others to the patients and the orthodontic appliances used. These three sets of factors were covered in the first part of this article. This second part deals with the biologic limitations of orthodontic treatment.

CLINICAL RELEVANCE

General dental practitioners and novice orthodontic practitioners may get into difficulties by embarking upon an orthodontic treatment which may not be feasible due to various limitations imposed by the underlying biology. This article provides a brief outline of these limitations.

Evaluating the effectiveness of school-based dental health education program among children of different socioeconomic groups

The aim of the present study was to evaluate the effectiveness of Dental Health Education programs among school children of different socioeconomic groups. The investigators made a visit to three different schools and studied 500 children. A ten items, open-ended, self-administered questionnaire was pretested on the primary and higher primary school children before and after an educational intervention. A second visit was made to one of the schools 1 year later and the same questionnaire was re-administered to those subjects who had participated in the original study. Results showed that although educational intervention was successful in improving the Dental health awareness of most children, the socioeconomic background is an important determinant for the same. Also, single-lecture technique seems to be inadequate in improving the knowledge of children in the long term.

[Oral manifestations of endocrine dysfunction]

Oral manifestations of endocrine dysfunction often may be observed initially by the dentist. Objective manifestations, such as ophtalmos in hyperthyroidism, signs of hypersecretion of GH in acromegaly, are easily recognized. Dentists should have some knowledge of many other diseases in this category that occasionally come in our attention. The present article will discuss the effects of over and under-secretion of each endocrine gland separately, showing its influence on the development and maintenance of the health of the teeth and supporting structures. Diabetes mellitus is the most common endocrinological disease, with an incidence of 3%. Periodontitis risk is three time greater in diabetic patients than in general population and it may worsen the diabetes evolution. Periodontitis in diabetic patients needs an rapid diagnosis and treatment. We also presents the oral aspects of thyroid, parathyroid, suprarenalian, growth hormone and female hormones pathology. The incidence of these troubles is less important, but oral manifestations may reveal an endocrine disfunction.

In sickness and in health

This final instalment in the literary series deals with the relationship between general and oral health and methods of maintaining good oral hygiene.

Influence of hot pressing on the microstructure and fracture toughness of two pressable dental glass-ceramics

Empress 1 and Empress 2 are well-known pressable all-ceramic dental materials that have generated substantial interest for many clinicians and patients. These two materials are reputed to benefit from heat pressing during the laboratory fabrication procedures, leading to better crystal distribution within a glass matrix, and hence an improved strength. The present study aimed to evaluate the effect of heat pressing on fracture toughness, microstructural features, and porosity. Results showed that Empress 1 had similar fracture toughness values before the pressing procedure, after it, and after the repressing procedure. The microstructural features were also similar among these specimens, but a more uniform distribution of leucite crystals was observed following the pressing and repressing procedures. Empress 2 demonstrated two different fracture toughness values. This was associated with the alignment of lithium disilicate crystals that occurred after the pressing and repressing procedures, which led to different indentation induced crack lengths, depending upon whether cracks propagated parallel to or perpendicular to the aligned crystals, the former having lower toughness than those that propagated in the perpendicular direction. Porosity, in terms of both the size and number of pores, was found to decrease after the pressing and repressing procedures for both materials. Repressing resulted in significant growth of the lithium disilicate crystals in Empress 2, but there was no change for the leucite crystals in Empress 1. The change in the lithium disilicate crystals' size did not have a noticeable effect on the fracture toughness of Empress 2. It was concluded that heat pressing did not significantly affect the fracture toughness of Empress 1, but resulted in two different values for Empress 2. It also decreased the size and number of pores for both materials, which could contribute to the strength improvement found after heat pressing, which has been reported in previous studies.