Computerized infrared thermographic imaging and pulpal blood flow: Part 1. A protocol for thermal imaging of human teeth

AIM

To observe the thermographic appearance of teeth and to develop a suitable protocol for imaging teeth in human subjects using modern thermographic imaging (TI) equipment in a thermologically controlled environment.

METHODOLOGY

The emissivity of enamel was investigated using an extracted incisor tooth. A total of 12 unrestored maxillary lateral incisors in six healthy patients were then imaged under rubber dam after a 20-min equilibration period and the thermographic data analysed using a dedicated software package. Recordings were made from standardized gingival and incisal sites on each tooth and the temperature gradient established for each tooth. Subsequently, a sequence of images of both maxillary central incisors in one patient was stored every 30 s during a 20-min equilibration period with and without an air-conditioning unit in operation.

RESULTS

For the lateral incisors there was a consistent temperature gradient (mean 1.28 degrees C) from gingival area to incisal area and there were no statistically significant differences between right and left sides for the gingival site (t = 0.34, NS) or the incisal site (t = 0.62, NS). The air-conditioning unit had a rapid and profound cooling effect. With the air-conditioning disabled there was a mean tooth surface temperature increase of 1.1 degrees C from 0 to 5 min of the equilibration period and 0.3 degree C from 15 to 20 min.

CONCLUSIONS

There was no significant difference in gingival or incisal temperatures between pairs of contralateral maxillary lateral incisors and a consistent temperature gradient existed from gingival to incisal areas of healthy maxillary lateral incisor teeth. The protocol described is suitable for TI of vital teeth. However, TI measured tooth surface temperature only which was extremely sensitive to air currents. A 15-min acclimatization period under rubber dam was adequate to allow stable tooth surface temperature measurement.

Computerized infrared thermographic imaging and pulpal blood flow: Part 2. Rewarming of healthy human teeth following a controlled cold stimulus

AIM

To investigate the rewarming pattern and rewarming rate of clinically healthy teeth following a controlled cold stimulus using TI techniques.

METHODOLOGY

A controlled cold stimulus was developed using an air stream at 20 degrees C. Gingival and incisal sites on 12 healthy maxillary lateral incisors in six patients were imaged under rubber dam following 20 s cooling. Images were captured at 10 s intervals during a 3-min rewarming period and the data used to construct graphs of the rewarming rate. Log transformation of the data was used to produce 'best fit' straight line graphs. Linear regression analysis was used to examine three variables, viz. the side of the mouth (right or left), the site of measurement (gingival or incisal) and the phase of rewarming (early 0-90 s, late 91-180 s).

RESULTS

The mean temperature change (delta t degree C) during rewarming was 8.5 degrees C (SD 1.0 degree C) for gingival sites and 7.2 degrees C (SD 1.1 degrees C) for incisal sites. The slope of the 'best fit' straight line data enabled a rewarming index to be calculated for each site on each tooth. Linear regression analysis showed that the phase of rewarming was highly significant but the other variables were not. A one-way ANOVA showed no significant differences between or within groups.

CONCLUSIONS

Three min is an appropriate time to record rewarming of teeth cooled for 20 s with an airstream at 20 degrees C. The side or site used to record surface temperatures using this technique is not significant. Rewarming is exponential and log transformation of the data produces a well-fitting straight line graph. The slope of this line provides a rewarming index which should enable comparison of TI and laser Doppler flowmetry in determining pulpal blood flow as a measure of tooth vitality.

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry

OBJECTIVE

To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period.

DESIGN

Retrospective immunocytochemical longitudinal study of archival serial biopsies.

MATERIALS AND METHODS

Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark).

RESULTS

Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient.

CONCLUSION

These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.

Carboxypeptidase-mediated metabolism of calcitonin gene-related peptide in human gingival crevicular fluid--a rôle in periodontal inflammation?

BACKGROUND

Metabolism by peptidases plays an important rôle in modulating the levels of biologically-active neuropeptides. The metabolism of the anti-inflammatory neuropeptide calcitonin gene-related peptide (GCRP), but not the pro-inflammatory neuropeptides substance P (SP) and neurokinin A (NKA) by components of the gingival crevicular fluid (GCF), could potentiate the inflammatory process in periodontitis.

AIMS

To characterise the extracellular hydrolysis of CGRP as a mechanism for the selective inactivation of this neuropeptide in GCF from periodontitis sites.

METHODS

Samples of GCF from periodontitis patients and periodontally-healthy subjects were incubated with synthetic human SP, NKA or CGRP. Reaction between the GCF constituents and synthetic peptides was allowed to progress from 0-180 min. Results of neuropeptide metabolism at each time were analysed by matrix-assisted laser desorption/ionisation mass spectrometry.

RESULTS

There was no evidence of metabolism of SP, NKA or CGRP by constituents of healthy GCF. Metabolism of synthetic SP and NKA was minimal even after extensive incubation with periodontitis GCF. However, loss of carboxy-terminal amino acids was evident after only 1 min incubation with periodontitis GCF. The pattern of CGRP metabolism, which proceeded from the C-terminus, indicated that the neuropeptide was degraded by a carboxypeptidase. After 180 min, there was extensive carboxypeptidase degradation of CGRP to an 11 amino acid peptide.

CONCLUSIONS

It is concluded that carboxypeptidase activity in GCF from periodontitis patients is responsible for rapid breakdown of CGRP but not SP or NKA. The rapid action of this carboxypeptidase on the anti-inflammatory neuropeptide CGRP is suggestive of a pathophysiological rôle for the enzyme in selectively degrading CGRP, thereby potentiating periodontal inflammation.

Changes in substance P and neurokinin A in gingival crevicular fluid in response to periodontal treatment

BACKGROUND

The study of periodontitis provides a unique model for assessing the involvement of neuropeptides in inflammatory disease.

AIM

To investigate the effects of periodontal treatment, resulting in a return to periodontal health, on the levels of substance P (SP) and neurokinin A (NKA) in gingival crevicular fluid (GCF).

METHOD

We completed a cause of non-surgical treatment for 8 subjects with periodontitis (6 females 2 males, mean age 45.1, range 38-67 years) started a course of non-surgical periodontal treatment. Clinical indices were measured at 2 periodontitis sites at the initial visit and at 8 weeks after the completion of treatment in each subject. A 30-s sample of GCF was collected from each test site using perio paper strips. Each strip was placed into 500 microl of ice cold 0.1 M PBS, pH 7.4, vortex mixed for 30 s, and then stored at -70 degrees C until analysed by radioimmunoassay.

RESULTS

The clinical condition of all test sites improved as a result of the periodontal treatment. The levels (pg/30 s sample) of SP fell from 56.3 (SD 66.0) at the initial visit to 4.2 (3.1) after treatment, p=0.017. The concentration (pg/microl) of SP in GCF fell from 140.6 (175.6) to 24.2 (11.1), p=0.036. The levels of NKA fell from 30.5 (17.1) to 10.6 (4.9), p=0.012 whereas the concentration changed little from 85.4 (43.5) to 61.6 (15.1), p=0.41.

CONCLUSION

The reduction in inflammation resulting from effective periodontal treatment is associated with a reduction in the levels of tachykinins in gingival crevicular fluid.

A comparison of thermocouple and infrared thermographic analysis of temperature rise on the root surface during the continuous wave of condensation technique

AIM

This study was designed to use two methods of temperature measurement to analyse and quantify the in vitro root surface temperature changes during the initial stage of the continuous wave technique of obturation of 17 single-rooted premolar teeth with standard canal preparations.

METHODOLOGY

A model was designed to allow simultaneous temperature measurement with both thermocouples and an infrared thermal imaging system. Two thermocouples were placed on the root surface, one coronally and the other near the root apex. A series of thermal images were recorded by an infrared thermal imaging camera during the downpack procedure.

RESULTS

The mean temperature rises on the root surface, as measured by the two thermocouples, averaged 13.9 degrees C over the period of study, whilst the infrared thermal imaging system measured an average rise of 28.4 degrees C at the same sites. Temperatures at the more apical point were higher than those measured coronally. After the first wave of condensation, the second activation of the plugger in the canal prior to its removal always resulted in a secondary rise in temperature. The thermal imaging system detected areas of greater temperature change distant from the two selected thermocouple sites.

CONCLUSIONS

The continuous wave technique of obturation may result in high temperatures on the external root surface. Infrared thermography is a useful device for mapping patterns of temperature change over a large area.

Response to replacement iron therapy in sideropenic individuals with recrudescent herpes labialis

This study investigated the effects of iron replacement on the incidence of recurrent herpes labialis and serum ferritin levels in patients with sideropenia. Ten patients with diagnosed sideropenia and a history of recrudescent herpes labialis were prescribed ferrous sulphate for a period of 3 months. Patients were questioned on the number of episodes of recrudescent herpes labialis that developed per month before treatment and the number of episodes of recrudescent herpes labialis that developed per month after the commencement of replacement iron therapy and during the follow-up period. All blood samples were collected by venipuncture for assay of ferritin levels. Serum ferritin levels were significantly increased compared to pretreatment levels (P<0.05). The number of monthly episodes of recrudescent herpes labialis was reduced from 0.78 to 0.2 episodes per month following treatment (P<0.05). The findings of this study suggest that iron replacement therapy should be further studied as a treatment option in sideropenic individuals with frequent recurrences of recrudescent herpes labialis.

Factors affecting the adhesion of Candida albicans to epithelial cells of insulin-using diabetes mellitus patients

This study investigated the influence of the carbon source of the growth medium, strains of Candida albicans and source of epithelial cells, and the influence of smoking and gender, on the adhesion of C. albicans to epithelial cells from insulin-using diabetic patients. Adhesion was determined by an autologous adhesion assay with exfoliated buccal or palatal epithelial cells and one strain of C. albicans isolated from each patient. The type strain CBS 562 was also used. Glucose or sucrose were used as the predominant carbon sources of the growth medium. The autologous strain of C. albicans adhered selectively to the oral mucosa of diabetic patients. Palatal epithelial cells retained significantly more C. albicans in vivo and adhesion was influenced by the availability of sugars in the growth medium and the strain of C. albicans.

Isolation of C. dubliniensis from insulin-using diabetes mellitus patients

The identification of the novel candidal species, C. dubliniensis, from oral swab studies of HIV-seropositive and -seronegative individuals has led to speculation that such a species may also reside in the oral cavity of other patient groups. In this study involvement of the newly described species, C. dubliniensis, was investigated in oral carriage and disease in 414 insulin-using diabetes mellitus patients. Seventy-seven percent of the diabetic patients carried candidal species in the oral cavity. C. albicans was the most commonly identified candidal species. This was followed by C. dubliniensis, which was isolated on 64 occasions. Colonisation with multiple candidal species was common, and C. dubliniensis was present in both carriage and disease states. Seven patients without signs of oral disease had C. dubliniensis isolated as the sole candidal species, while the same species was associated with various forms of oral candidosis in six patients.

A comparison of four extraction methods for substance P, neurokinin A and calcitonin gene-related peptide from human dental pulp tissue

Measuring neuropeptides in biological tissues by radioimmunoassay requires efficient extraction that maintains their immunoreactivity. Many different methods for extraction have been described, but there is little information on optimal extraction methods for individual neuropeptides from human dental pulp tissue. The aim was therefore to identify an effective extraction procedure for three pulpal neuropeptides; substance P, neurokinin A and calcitonin gene-related peptide. Tissue was obtained from 20 pulps taken from teeth freshly extracted for orthodontic reasons. The pulp samples were divided into four equal groups and different extraction methods were used for each group. Boiling whole pulp in acetic acid gave the highest overall yield and, in addition, offered an easy and rapid means of pulp tissue processing. The use of protease inhibitors did not increase the recovery of the immunoreactive neuropeptides but did provide the best combination of maximal recoveries and minimal variability. These results should be useful for planning the extraction of these neuropeptides from human pulp tissue in future studies.

Burning mouth in Parkinson's disease sufferers

OBJECTIVE

The purpose of the study was to determine the prevalence of burning mouth (BM) in a population of Parkinson's Disease (PD) sufferers and also to assess the use of pain profiles in identifying the type of burning sensation experienced.

DESIGN

Subjects were surveyed by means of a one shot postal questionnaire for which ethical approval had previously been granted. Anonymity was guaranteed and therefore no attempt was made to follow up non-respondents.

MAIN OUTCOME

BM was reported by 24% of respondents. The pain profiles were completed by 17 BM sufferers.

CONCLUSION

Burning mouth is reported to occur in 24% of PD sufferers which is 5 times greater than that of the general population. The reason for this is uncertain but the result has implications for the future care of PD patients and indicates the need for increased dental input at PD outpatient clinics.

Antioxidant status of oral mucosal tissue and plasma levels in smokers and non-smokers

The antioxidant status of an individual is thought to be important in the development of potentially malignant oral lesions (PMOL) and oral squamous cell carcinoma (OSCC). To date, little detailed information on mucosal antioxidant status is available in a United Kingdom population and neither has the relationship between smoking and mucosal antioxidant status been established. Furthermore, it has been implied that serum levels of antioxidants and tissue levels in the oral mucosa should be equivalent, but that is unproven. To address these deficiencies in our knowledge we studied 60 individuals, all of whom had an oral mucosal biopsy and simultaneous venous blood sampling. Antioxidant levels were measured using high performance liquid chromatography. Smokers (n= 19) were found to have significantly lower levels of plasma beta-carotene (P<0.05) and significantly lower levels of tissue alpha-carotene (P<0.05) than non-smokers (n=41). Tissue alpha-carotene correlated with plasma levels, but this was not the case with alpha-tocopherol, retinol, lycopene or beta-carotene. This is the first data on oral mucosal antioxidant levels and provides baseline data from which to study patients with potentially malignant oral lesions and oral squamous cell carcinoma.

Oral candidal carriage and infection in insulin-treated diabetic patients

AIM

To evaluate candidal load and carriage of candidal species in 414 insulin-treated diabetes mellitus patients with and without clinical signs of infection. Host factors that could influence candidal load in diabetic patients with oral candidosis were also investigated.

METHODS

Candidal species were recovered from 414 insulin-treated diabetes mellitus patients attending two hospital diabetic clinics, using an oral rinse technique.

RESULTS

Seventy-seven per cent of diabetic patients carried Candida species in their oral cavity, with C. albicans being the species most frequently isolated. C. dubliniensis was found for the first time in this patient group. Forty per cent of patients colonized with candidal species had no clinical signs of oral candidosis. Where oral candidosis was present, erythematous candidosis was the most common clinical presentation. Candidal load was not associated with age, sex or glycaemic control. However, it was significantly increased in those patients who were tobacco smokers, and non-significantly increased in those patients who wore dentures, or who had clinical signs of oral candidosis.

CONCLUSION

The epidemiology of oral candidal carriage and infections in diabetic patients is complex and includes species which have not been previously reported in this group of patients. The development of oral candidosis in insulin-treated diabetes mellitus patients is not the result of a single entity, but rather, a combination of risk factors.

Minocycline-induced staining of the adult permanent dentition: a review of the literature and report of a case

Tetracycline staining of teeth during tooth development is well documented. We report here the rarer condition of tetracycline staining of adult teeth. This occurrence appears to involve enamel surface demineralization/remineralization and can produce staining clinically indistinguishable from that occurring during tooth development.

Thermal image analysis of electrothermal debonding of ceramic brackets: an in vitro study

This study used modern thermal imaging techniques to investigate the temperature rise induced at the pulpal well during thermal debonding of ceramic brackets. Ceramic brackets were debonded from vertically sectioned premolar teeth using an electrothermal debonding unit. Ten teeth were debonded at the end of a single 3-second heating cycle. For a further group of 10 teeth, the bracket and heating element were left in contact with the tooth during the 3-second heating cycle and the 6-second cooling cycle. The average pulpal wall temperature increase for the teeth debonded at the end of the 3-second heating cycle was 16.8 degrees C. When the heating element and bracket remained in contact with the tooth during the 6-second cooling cycle an average temperature increase of 45.6 degrees C was recorded.

Calcitonin gene-related peptide in gingival crevicular fluid in periodontal health and disease

The aims of the present study were to investigate whether calcitonin gene-related peptide (CGRP) was present in gingival crevicular fluid in both periodontal health and disease and to study the relationship with periodontal inflammation. Gingival crevicular fluid (GCF) was collected from a healthy, a gingivitis and a periodontitis site in 18 subjects with periodontitis and from a healthy site in 19 subjects without periodontitis. The volume of GCF was measured and each sample subsequently analysed for CGRP by radioimmunoassay. In subjects with periodontitis, CGRP immunoreactivity (CGRP-IR) was not detected in any periodontitis sites, nor in 67% of gingivitis and 28% of periodontally-healthy sites. The total amount of CGRP-IR was significantly elevated in periodontally healthy (p=0.0015) and gingivitis (p=0.027) compared with periodontitis sites. CGRP-IR was present in 89% of the healthy sites sampled in control subjects at comparable levels to those in healthy sites in periodontitis subjects. It is concluded that in periodontal inflammation, particularly in deep pockets, constituents of GCF process and degrade CGRP.

A comparison of the management of potentially malignant oral mucosal lesions by oral medicine practitioners and oral & maxillofacial surgeons in the UK

This study describes the results of a survey undertaken to assess the management of potentially malignant oral mucosal lesions by oral medicine practitioners and compares their approach with that of oral & maxillofacial surgeons that we have previously described. Significant differences were noted between the two groups in the use of photography to document the lesions and in the use of certain special investigations, which included measurement of serum iron, serum ferritin, serum Vit B12, red cell folate and candidal isolation. The groups also varied in the perceived importance of the age of the patient and anatomical site of the lesion when deciding on the need for further biopsy. There was also significant variation in the use of certain treatment modalities, including excising non-dysplastic and severely dysplastic/carcinoma in-situ lesions and eliminating trauma when treating mild/moderately dysplastic and severely dysplastic/carcinoma in-situ lesions. Significant differences in the frequency and duration of follow-up were noted for non-dysplastic lesions. Finally, the two groups differed significantly when asked to rank the perceived importance of certain factors (the histopathology of the most recent biopsy and the anatomical site of the lesion) when deciding the need to follow-up. Possible reasons for the variation are discussed.

Buccinator window anomaly

Four patients, three women and one man, with a mean age of 32 years, presented with a history of recurrent parotid swelling. In the women the swelling was unilateral. All had previously undergone sialography using a hand injection technique and no structural abnormality was demonstrated. Sialography was repeated using a continuous-infusion pressure-monitored system. In all cases an initial very high filling pressure (>200 mmHg) was recorded followed by a rapid reduction in pressure and a more normal filling pressure pattern. The duct system and glands all appeared morphologically normal. Treatment with acrylic appliance therapy and an intraductal catheter was attempted with some success.

Burning mouth syndrome: approach to successful management

Burning mouth syndrome is a fairly common condition. Contrary to popular belief, its management is successful in about 70% of cases--provided a structured protocol based on scientific evidence is adopted. Specialist advice must be sought in some cases, but many patients can be successfully treated in the primary care environment.

Oral white sponge naevus: response to antibiotic therapy

White sponge naevus is a rare benign inherited disorder of the mucous membranes, principally the oral mucosa. Although the condition is painless, patients are often symptomatic, complaining of an altered texture of the mucosa or that the lesions are unaesthetic. No standard treatment for the condition exists although numerous treatments have been tried. We now report on six patients who were prescribed systemic antibiotic therapy; three were adult men aged 24 years, 32 years, and 52 years, one an 11-year-old woman, one a 6-year-old woman (daughter of the 32-year-old man) and an 18-month-old boy (son of the 24-year-old man). Four responded as judged by clinical examination, although not the 6-year-old female or the 18-month-old male; the discontinuation of therapy then resulted in clinical recurrence in those who had responded, but long-term low dose treatment maintained the remission.

Acyclovir cream prevents clinical and thermographic progression of recrudescent herpes labialis beyond the prodromal stage

Early treatment of recrudescent herpes labialis over the symptomatic area has been claimed to inhibit the clinical signs of recrudescent herpes labialis. Electronic infrared thermography can both recognise the prodromal phase and identify the area requiring drug therapy. Our objective was to use infrared thermography to identify prodromal herpes and follow the response to topical acyclovir cream therapy over the thermographically active area. Seventy instances of prodromal cold sores were confirmed thermographically. Zovirax cold sore cream (acyclovir) was applied 5 times per day for 5 days to the thermographically positive area. All returned after 72 h for a further thermographic and clinical examination of the initially active area. All 70 patients illustrated a localised increase in temperature over the symptomatic area during the prodromal stage. The development of a clinical herpes lesion was prevented in 46% of the patients. In the lesions that did develop, an 80% reduction in clinical lesion size was observed in 82% of the subjects. The remaining 18% showed a reduction in healing time.

Recrudescent herpes simplex infection mimicking primary herpetic gingivostomatitis

We report six cases of recrudescent intraoral herpes simplex infection clinically indistinguishable from primary herpetic gingivostomatitis. All infections occurred in healthy children or young adults. Serological analysis demonstrated herpes simplex virus (HSV)-specific IgG at initial presentation, indicating that the infection was not a primary infection. Convalescent sera exhibited HSV-specific IgM and a rising HSV-specific IgG titre. These findings demonstrate that the initial clinical diagnosis of primary herpetic gingivostomatitis was erroneous and that what was actually being observed was widespread recrudescent intraoral herpes simplex infection.