Immunocytochemical investigation of immune cells within human primary and permanent tooth pulp

AIM: The aim of this study was to determine whether there are any differences in the number and distribution of immune cells within human primary and permanent tooth pulp, both in health and disease. DESIGN: The research took the form of a quantitative immunocytochemical study. One hundred and twenty-four mandibular first permanent molars and second primary molars were obtained from children requiring dental extractions under general anaesthesia. Following exodontia, 10-microm-thick frozen pulp sections were processed for indirect immunofluorescence. Triple-labelling regimes were employed using combinations of the following: (1) protein gene product 9.5, a general neuronal marker; (2) leucocyte common antigen (LCA); and (3) Ulex europaeus I lectin, a marker of vascular endothelium. Image analysis was then used to determine the percentage area of immunostaining for LCA. RESULTS: Leucocytes were significantly more abundant in the pulp horn and mid-coronal region of intact and carious primary teeth, as compared to permanent teeth (P < 0.05, anova). Both dentitions demonstrated the presence of well-localized inflammatory cell infiltrates and marked aborization of pulpal nerves in areas of dense leucocyte accumulation. CONCLUSIONS: Primary and permanent tooth pulps appear to have a similar potential to mount inflammatory responses to gross caries The management of the compromised primary tooth pulp needs to be reappraised in the light of these findings.     

Vanilloid receptor 1 expression in human tooth pulp in relation to caries and pain

AIMS: To investigate the presence of vanilloid receptor 1 (TRPV1) in human dental pulp and to correlate any expression with caries and pain. METHODS: Permanent mandibular first molars were collected and categorized as intact or grossly carious. Grossly carious teeth were further categorized as carious asymptomatic or carious painful samples. Coronal pulps were removed and processed for indirect immunofluorescence using antibodies raised against TRPV1 and a neuronal marker, either protein gene product 9.5 or alpha-smooth muscle actin, in conjunction with Ulex europaeus agglutinin 1 lectin to fully label the pulp vasculature. RESULTS: Analysis revealed that TRPV1 labeling was not confined to pulpal nerve fibers. TRPV1 was also consistently expressed within pulp microvasculature. Expression of neuronal TRPV1 was significantly increased throughout the pulp in grossly carious samples (P < .05). No significant differences were found between carious asymptomatic and carious painful samples. A significant increase in vascular TRPV1 expression was observed in arterioles present in the midcoronal pulp in carious painful compared with carious asymptomatic samples (mean area +/- SEM [%] of TRPV1 to vascular labeling; 6.48% +/- 4.5% for carious asymptomatic teeth, n = 9; 31.21% +/- 9.6% for carious painful teeth, n = 9; P = .02). CONCLUSION: Expression of TRPV1 in pulpal nerve fibers undergoes marked changes with caries. This may be of relevance in the development of pulpal inflammation, but its relationship to dental pain is still unclear. However, vascular TRPV1 expression does appear to be positively correlated with dental pain, thus providing new insights into symptomatic pulpitis.     

Substance P expression in human tooth pulp in relation to caries and pain experience

The neuropeptide substance P (SP) is found within a subpopulation of nociceptive afferent nerve fibres and has been shown to be upregulated in a variety of sites following peripheral inflammation. The aim of this study was to investigate the expression of SP within human teeth, both in health and disease, and to seek a correlation between reported pain history and SP expression within pulpal nerves. Coronal pulps were removed from 62 permanent mandibular molars with a known pain history. Teeth were categorised as intact, moderately or grossly carious. Using indirect immunofluorescence, sections were double-labelled for the general neuronal marker protein gene product 9.5 (PGP 9.5) and for SP. Image analysis was then used to quantify the percentage area of PGP 9.5-labelled tissue which was also labelled for SP. Throughout the pulp, the expression of SP was found to be significantly increased with the progression of caries. Furthermore, SP expression was significantly greater in grossly carious painful specimens than in grossly carious asymptomatic specimens. These data would suggest that the expression of SP within pulpal nerves undergoes dynamic changes following caries, which may have an important clinical significance in terms of inflammation and pain experience.     

Histological evaluation of teeth with hyperplastic pulpitis caused by trauma or caries: case reports

AIM: The purpose of this histological study was to examine teeth with hyperplastic pulpitis caused by trauma or caries. SUMMARY: The pulp tissue of one young permanent incisor with a complicated crown-root fracture and a hyperplastic pulpitis, which had been contaminated with oral microflora for 40 days, and pulp polyps from four permanent first molars whose crowns were destroyed by extensive caries were prepared for standard histological examination. Histologically, normal pulp tissue organization was observed in the tooth with a complicated crown-root fracture in the cervical radicular region. Irregular calcification was seen in the coronal and radicular portion of the pulp in the four carious teeth with pulp polyps. Radicular pulp tissue in the middle and apical third of root canals beneath irregular calcification showed intensive fibrosis but was free from inflammatory cells. KEY LEARNING POINTS: Hyperplastic pulpitis is a type of irreversible chronic open pulpitis. Young permanent teeth with hyperplastic pulpitis caused by trauma or caries have a great inherent defensive capacity to heal.     

Pulpal status of human primary teeth with physiological root resorption

Objective.  The overall aim of this study was to determine whether any changes occur in the pulpal structure of human primary teeth in association with physiological root resorption.
Methods.  The experimental material comprised 64 sound primary molars, obtained from children requiring routine dental extractions under general anaesthesia. Pulp sections were processed for indirect immunofluorescence using combinations of: (i) protein gene product 9.5 (a general neuronal marker); (ii) leucocyte common antigen CD45 (a general immune cell marker); and (iii) Ulex europaeus I lectin (a marker of vascular endothelium). Image analysis was then used to determine the percentage area of staining for each label within both the pulp horn and mid-coronal region. Following measurement of the greatest degree of root resorption in each sample, teeth were subdivided into three groups: those with physiological resorption involving less than one-third, one-third to two-thirds, and more than two-thirds of their root length.
Results.  Wide variation was evident between different tooth samples with some resorbed teeth showing marked changes in pulpal histology. Decreased innervation density, increased immune cell accumulation, and increased vascularity were evident in some teeth with advanced root resorption. Analysis of pooled data, however, did not reveal any significant differences in mean percentage area of staining for any of these variables according to the three root resorption subgroups ( P  > 0.05, analysis of variance on transformed data).
Conclusions.  This investigation has revealed some changes in pulpal status of human primary teeth with physiological root resorption. These were not, however, as profound as one may have anticipated. It is therefore speculated that teeth could retain the potential for sensation, healing, and repair until advanced stages of root resorption.     

Innervation of human tooth pulp in relation to caries and dentition type

The neural status of carious teeth, particularly those associated with a painful pulpitis, is largely unknown. This study sought to determine differences in the innervation density of human primary and permanent teeth and whether caries or painful pulpitis was associated with anatomical changes in pulpal innervation. Coronal pulps were removed from 120 primary and permanent molars with a known pain history. Teeth were categorized as intact, moderately carious, or grossly carious. Using indirect immunofluorescence, we labeled sections for the general neuronal marker, protein gene product 9.5. Using image analysis, we found permanent teeth to be significantly more densely innervated than primary teeth. While there was no significant correlation with reported pain experience, neural density in both dentitions increased significantly with caries. Analysis of these data suggests that caries-induced changes in neural density may be functionally more important in the regulation of pulpal inflammation and healing than in the processing and perception of dental pain.     

Confocal laser scanning microscopic analysis of the depth of dentin caries-like lesions in primary and permanent teeth

This study analyzed comparatively, by confocal laser scanning microscopy (CLSM), the depth of caries-like lesions produced by biological and chemical artificial models in permanent and primary dentin. Six primary molars and six premolars were used. The occlusal enamel was removed and a nail polish layer was applied on the specimens, except for a 4 x 2 mm area on dentin surface. Half of specimens were immersed in acid gel for 14 days (chemical model) and the other half was immersed in BHI broth with S. mutans for 14 days (biological model). After development of artificial caries, the crowns were longitudinally sectioned on the center of the carious lesion. Three measurements of carious dentin depth were made in each specimen by CLSM. Measurements depths were compared between the caries models and between tooth types by one-way ANOVA and Tukey test (a=5%). For permanent teeth, the biological model showed significantly higher (p<0.05) caries depth values than the chemical model. For primary teeth, no statistically significant difference (p>0.05) was found between the caries models. The artificial caries model influenced caries depth only in permanent teeth. There was no difference in carious dentin depth between permanent and primary teeth, regardless of the artificial caries model.     

Histological comparison of pulpal inflammation in primary teeth with occlusal or proximal caries

Objective.  A number of clinical and histological studies have investigated caries-related changes in the primary tooth pulp, but the effect of caries site, as a clinical variable, has not been previously considered. This study sought to compare inflammatory changes within the pulp of primary molars according to the location of the caries lesion (occlusal or proximal).
Methods.  Eighty-three primary molars were extracted under general anaesthesia for caries and/or orthodontic reasons, and were split immediately after removal and fixed in 10% formalin. Teeth were then decalcified, sectioned, and stained with haematoxylin and eosin for histological examination using light microscopy. Caries depth was measured using a graticle, and the site of the caries lesion noted as occlusal or proximal. Samples were further classified into one of five subgroups according to the observed degree of pulpal inflammation.
Results.  Key findings were that where caries depth was less than 50% of the total dentine thickness, there were no significant differences in inflammatory status according to caries site. In contrast, marked inflammatory changes were significantly more likely throughout the coronal pulp of teeth with proximal caries compared to teeth with occlusal caries where caries depth was equal to, or greater than, 50% of the total dentine thickness ( P  = 0.017, Fisher's exact test).
Conclusion.  Primary teeth with proximal carious lesions extending more than 50% through the dentine thickness appear to have more extensive inflammatory pulpal changes than teeth with occlusal caries of a similar depth. This finding has clinical implications and may help inform treatment decisions in the management of primary teeth with deep carious lesions.     

Pulp changes in deciduous teeth associated with deep carious dentine.

Serial sections of carious deciduous molar teeth were examined and it was found that inflammation of the pulp occurred when the average thickness of remaining dentine between the most deeply penetrating bacteria and the pulp was 0·6 mm, and the maximal width of dentine between the pulp and the most deeply penetrating bacteria associated with pulpitis was 1·8 mm. The comparable figures for permanent teeth noted by Shovelton (1968) were 0·3 mm and 0·8 mm. This indicates that the deciduous pulp responds more rapidly to the effects of dentine caries than does the permanent tooth, and emphasizes the value of preventing caries of deciduous teeth or at least providing early restorative care.     

Rural and urban disparities in caries prevalence in children with unmet dental needs: the New England Children's Amalgam Trial

OBJECTIVES: To compare the prevalence of caries between rural and urban children with unmet dental health needs who participated in the New England Children's Amalgam Trial. METHODS: Baseline tooth and surface caries were clinically assessed in children from rural Maine (n = 243) and urban Boston (n = 291), who were aged 6 to 10 years, with two or more posterior carious teeth and no previous amalgam restorations. Statistical analyses used negative binomial models for primary dentition caries and zero-inflated models for permanent dentition caries. RESULTS: Urban children had a higher mean number of carious primary surfaces (8.5 versus 7.4) and teeth (4.5 versus 3.9) than rural children. The difference remained statistically significant after adjusting for sociodemographic factors and toothbrushing frequency. In permanent dentition, urban children were approximately three times as likely to have any carious surfaces or teeth. However, rural/urban dwelling was not statistically significant in the linear analysis of caries prevalence among children with any permanent dentition caries. Covariates that were statistically significant in all models were age and number of teeth. Toothbrushing frequency was also important for permanent teeth. Conclusions: Within this population of New England children with unmet oral health needs, significant differences were apparent between rural and urban children in the extent of untreated dental decay. Results indicate that families who agree to participate in programs offering reduced cost or free dental care may present with varying amounts of dental need based on geographic location.     

Descriptors of permanent teeth with cariously exposed pulp in patients presenting at a Nigerian hospital

Abstract

Aim. To describe the pattern of presentation of carious permanent teeth with pulp exposure and to determine factors associated with choice of treatment for such teeth. Materials and methods. All patients presenting at the oral diagnosis clinic of Lagos University Teaching Hospital Dental centre between January 2009 and June 2009 were examined and those with carious lesion involving the pulp were included in the study. The history and character of pain from teeth, extent of tooth structure lost, proposed treatment and reason for proposed treatment was recorded. Results. The tooth most affected by pulp exposure due to caries is the lower first molar (17.5%). Extraction was the treatment of choice for many patients due to the following reasons: obliterated root canals (30%), patients' preference (30%) and non-restorable teeth (22%). Conclusion. Extraction was the predominant treatment chosen for cariously exposed permanent teeth due to the condition of the tooth.     

Endodontic treatment in the primary dentition

A number of factors are involved in the development of pulp and periapical disease in primary and permanent teeth, with dental caries being the main factor. Although these factors are similar, the clinical management of a primary or permanent tooth with pulp or periapical disease may be quite different. This is based mainly on the differences between the two types of teeth, with primary tooth longevity, coronal structural integrity, root canal morphology, and root anatomy being important features to be taken into account when treatment planning. This paper reviews some aspects of primary teeth and the various treatment options for the management of pulp and periapical disease.     

Comparison of mechanical and chemomechanical methods of caries removal in deciduous and permanent teeth: A SEM study

Background: Mechanical method of caries removal is associated with the removal of sound tooth structure, production of pain, heat, annoying sounds, and vibrations. Chemomechanical caries removal method is based on removal of only carious dentin leaving sound dentin intact. Aim: The aim of this study was to compare the efficacy of mechanical and chemomechanical methods of caries removal in deciduous and permanent teeth. Study Design: A total of 30 carious teeth including 15 deciduous and 15 permanent teeth having dentinal caries selected randomly and cut into two halves through center of the lesion, were subjected to caries removal by mechanical (Group A), and chemomechanical methods (Group B). Time taken for removal of caries was noted with stopwatch. Samples were prepared and seen under the scanning electron microscope for the presence of bacterial colonies. Data were analyzed using statistical package for social sciences (SPSS) Software. Results: No significant difference was found for the presence of bacterial colonies in both groups of deciduous and permanent teeth; however, time taken for caries removal by the chemomechanical method was twice than the mechanical method. Conclusion: despite the insignificant presence of bacterial colonies and twice time taken as compared to mechanical method, chemomechanical method was easy to introduce, was painless, did not form smear layer and conserved the sound tooth structure.     

The occurrence of dental pain and extractions over a 3-year period in a cohort of children aged 3-6 years

OBJECTIVES: To describe the occurrence of dental pain and extractions in young children in relation to the caries and restoration history of their primary molar teeth. METHODS: A prospective cohort study of 739 children aged 2.8 to 6.2 years attending 50 dental practices in the North West of England followed for 3 years. Incidence rates for pain and extraction in primary molar teeth were calculated for children with and without dental caries. Tooth years at risk of extraction or pain were calculated for each primary molar according to whether they were caries-free, carious and unrestored, or restored. RESULTS: A total of 119 (16.1 percent) children had caries at recruitment and 157 developed caries during follow-up. Each year approximately one in five children with caries, but only one in 100, who was caries-free, presented with dental pain. In the whole population, each year, approximately one in 40 children had a primary molar tooth extracted but in children with caries it was one in 10. In the total cohort, incidence.of pain was higher in unrestored carious teeth than restored, but incidence of extraction was higher in restored than in unrestored teeth. CONCLUSION: The majority of children attending general dental practice remained caries-free and did not experience pain or extraction over 3 years. Children with caries had a substantial risk of developing pain or having an extraction. The study was unable to demonstrate that restoring carious primary molar teeth prevents pain and extraction.     

Electrical resistance correlation with tactile examination on occlusal surfaces.

Electrical resistance of the tooth was measured through the dental pulp by a relatively simple method. The primary resistance is in the enamel, and the total resistance drops severalfold as dental caries develop. This resistance has been measured on the occlusal surfaces of 122 teeth of children. The differences between explorer categories showed statistically different resistance values (P greater than 0.9995, excluding the offscale sound-tooth category). After 3 to 4 months, 9 of the 32 teeth of the incipient caries category became obviously carious, while none of the caries-free teeth became carious.     

Indirect pulp capping and primary teeth: is the primary tooth pulpotomy out of date?

Formocresol pulpotomy (FP) in the United States is most frequently used to treat asymptomatic caries near the pulp in primary teeth. Indirect pulp therapy (IPT) is also indicated and has a significantly higher long-term success. Pulpotomy is thought to be indicated for primary teeth with carious pulp exposures, but research shows the majority of such teeth are nonvital or questionable for treatment with vital pulp therapy. IPT has a significantly higher success in treating all primary first molars, but especially those with reversible pulpitis compared with FP. The purpose of this article was to review the dental literature and new research in vital pulp therapy to determine the following: (1) Is a pulpotomy indicated for a true carious pulp exposure? (2) Is there a diagnostic method to reliably identify teeth that are candidates for vital pulp therapy? (3) Is primary tooth pulpotomy out of date, and should indirect pulp therapy replace pulpotomy? )     

Complete or ultraconservative removal of decayed tissue in unfilled teeth

Background : The treatment of deep dental decay has traditionally involved removal of all the soft demineralized dentine before a filling is placed. However, this has been challenged in three groups of studies which involve sealing soft caries into the tooth. The three main groups either remove no caries and seal the decay into the tooth, remove minimal (ultraconservative) caries at the entrance to a cavity and seal the remaining caries in, or remove caries in stages over two visits some months apart to allow the pulp time to lay down reparative dentine (the stepwise excavation technique). Objectives : To test the null hypothesis of no difference in the incidence of damage or disease of the nerve of the tooth (pulp), progression of decay and longevity of restorations irrespective of whether the removal of decay had been minimal (ultraconservative) or complete. Search strategy : The Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PubMed and EMBASE databases were searched. The reference lists in relevant papers were checked. Selection criteria : Randomized controlled trials and controlled clinical trials comparing minimal (ultraconservative) caries removal with complete caries removal in unrestored permanent and deciduous teeth. Data collection and analysis : Outcome measures recorded were exposure of the nerve of the tooth (pulp) during caries removal, patient experience of symptoms of pulpal inflammation or necrosis, progression of caries under the filling, time until the filling was lost or replaced. Due to the heterogeneity of the included studies the overall estimate of effect was calculated using a random‐effects model. Main results : Four studies met the inclusion criteria; two stepwise excavation studies and two ultraconservative caries removal studies. Partial caries removal in symptomless, primary or permanent teeth reduces the risk of pulp exposure. We found no detriment to the patient in terms of pulpal symptoms in this procedure and no reported premature loss or deterioration of the restoration. Authors' conclusions : The results of this systematic review reject the null hypothesis of no difference in the incidence of damage or disease of the nerve of the tooth (pulp) irrespective of whether the removal of decay had been minimal (ultraconservative) or complete and accepts the null hypothesis of no difference in the progression of decay and longevity of restorations. However, the number of included studies is small and differ considerably. Partial caries removal is therefore preferable to complete caries removal in the deep lesion, in order to reduce the risk of carious exposure. However, there is insufficient evidence to know whether it is necessary to re‐enter and excavate further but studies that have not re‐entered do not report adverse consequences. Plain language summary : A systematic review of the literature revealed four studies comparing complete and minimal (ultraconservative) caries removal. It was found that partial caries removal in symptomless, primary or permanent teeth reduces the risk of pulp exposure. We found no detriment to the patient in terms of pulpal symptoms in this procedure. Therefore, partial caries removal is preferable to complete caries removal in the deep lesion, in order to reduce the risk of carious exposure. However, there is insufficient evidence to know whether it is necessary to re‐enter and excavate further but studies that have not re‐entered do not report adverse consequences.     

A cohort study on prevalence of dental caries concerning primary schoolchildren in one village of Niigata Prefecture

To review the previous preventive measures against the incidence of dental caries in children, we started to examine the state of dental health in children at the age of 18 months. The annual dental examination continued up to 12 years of age (sixgraders). Enrolled in this study were a total of 225 children living in a Town T and born between 1980 and 1982. Meanwhile, we made surveys in order to gauge the degree to which the subjects and their parents have concern for oral health. The findings and their relationships to the caries incidence were analyzed using an epidemiological technique. The annual dental examinations revealed that in primary dentition the incidence of caries tends to increase in 3-year-olds while in permanent dentition the carious process extends in 4–6 graders. By kind of teeth, primary molars accounted for 52% of the affected deciduous teeth. First molars made up 72% of all the decayed permanent teeth. Using the two caries cumulative indexes developed by our department for recording the prevalence and severity of tooth decay in the deciduous dentition and in the permanent dentition, respectively, we found that there is a correlation between the incidence of caries in the deciduous dentition and that in the permanent teeth. The two formulae are based on the cumulative number of decayed teeth that appeared in the deciduous dentition and permanent dentition for a given period of time. In order to find whether there is any correlation between caries attack and attention paid to the risk factors, we divided the subjects into two groups by the number of decayed teeth per person. In the group made up of those with many carious teeth, it was noted that between-meal snacks are most likely to produce caries in deciduous teeth, while lifestyle affects permanentteth.

     

Genetic influences on dental enamel that impact caries differ between the primary and permanent dentitions

Clinically, primary and permanent teeth are distinct anatomically and the presentation of caries lesions differs between the two dentitions. Hence, the possibility exists that genetic contributions to tooth formation of the two dentitions are different. The purpose of this study was to test the hypothesis that genetic associations with an artificial caries model will not be the same between primary and permanent dentitions. Enamel samples from primary and permanent teeth were tested for microhardness at baseline, after carious lesion creation, and after fluoride application to verify association with genetic variants of selected genes. Associations were found between genetic variants of ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, and matrix metallopeptidase 20 and enamel from permanent teeth but not with enamel from primary teeth. In conclusion, our data continue to support that genetic variation may impact enamel development and consequently individual caries susceptibility. These effects may be distinct between primary and permanent dentitions.