Prevalencia y Severidad de Caries Dental en los Niños Beneficiarios del Programa de Salud Oral Asociados a Escuelas de Chile / Prevalence and severity of dental caries in beneficiary children in the oral health program associated with schools in Chile

La caries es la enfermedad crónica más prevalente en niños constituyendo un problema de salud pública a nivel mundial. El objetivo de este estudio fue determinar la prevalencia y severidad de caries en niños y niñas pertenecientes al Programa de Salud Oral asociado a escuelas de la Junta Nacional de Auxilio Escolar y Becas (JUNAEB). Se realizó un estudio de corte trasversal basado en datos del año 2015 del Sistema Informático del Programa de Salud Oral de JUNAEB. Las variables de estudio fueron presencia y severidad de caries (índices ceod y COPD) y las variables de asociación exploratorias fueron zona geográfica, provincias, sexo, tipo de dependencia administrativa del colegio, tipo de enseñanza, sistema de salud, situación de extrema pobreza, tipo de dentición y tipo de atención. La asociación independiente entre las variables se analizó mediante el test de Chi2 y t-test. La muestra quedó constituida por 162.116 individuos, siendo el 50 % mujeres. La población estudiada mostró una prevalencia de 49 % y un índice ceod y COPD de 2,48 y 1,55 respectivamente. La mayor prevalencia (63 %) fue la zona centro sur y la región del Bío-Bío mostró los mayores índices de severidad (p<0,001). Las asociaciones más significativas fueron entre caries y el nivel socioeconómico y zona geográfica (p<0,001). Este estudio evidencia la asociación de la prevalencia/ severidad de caries y el nivel socioeconómico, y la distribución geográfica de la caries; lo cual hace necesario implementar medidas preventivas que compensen la ruralidad o la falta de fluoración del agua en algunas zonas geográficas de pobreza extrema.

Caries is the most prevalent chronic disease in children, constituting a worldwide public health problem. The aim of this study was to determine the prevalence and severity of caries in children included in the Oral Health Program associated to schools of the National Board of School Aid and Scholarships (JUNAEB). A cross- sectional study based on data from 2015 electronic register JUNAEB Oral Health Program was carried out. The main variables studied were presence and severity of caries (dmft and DMFT indices) and association variables were geographical area, sex, type of administrative dependency of the school, type of education, health system, and situation of extreme poverty, type of teething and type of care. The independent association between the variables was analyzed using the Chi2 test and the t-test.The sample consisted of 162,116 individuals, 50 % being women. The studied population showed a prevalence of 49 % and a CEOD and COPD index of 2.48 and 1.55, respectively. The highest prevalence (63 %) was the south-central zone and the Bío- Bío region showed the highest severity indices (p <0.001). The most significant associations were between caries and socioeconomic level and geographic area (p <0.001). This study shows the association between caries prevalence / severity and socioeconomic level, and the geographical distribution of caries, which make necessary the implementation of preventive measures that compensate rurality, or the lack of water fluoridation in some areas of extreme poverty.

Postradiation Matrix Metalloproteinase-20 Expression and Its Impact on Dental Micromorphology and Radiation-Related Caries.

Recent evidence suggests that head-and-neck radiotherapy (HNRT) increases active forms of matrix metalloproteinase-20 (MMP-20) in human tooth crowns, degrading the dentin-enamel junction (DEJ) and leading to enamel delamination, which is a pivotal step in the formation of radiation-related caries (RRC). Additional participation of enzymatic degradation of organic matrix components in caries progression was attributed to MMP-20 in dentin. Therefore, the current study tested the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes to the enamel and dentin. Thirty-six teeth were studied, including 19 post-HNRT specimens and 17 nonirradiated controls. Optical light microscopy was used to investigate the micromorphological components of the DEJ, dentin-pulp complex components, and carious dentin. The samples were divided into 2 subgroups: nondemineralized ground sections (n = 20) and demineralized histological sections (n = 16). In addition, immunohistochemical analysis using the immunoperoxidase technique was conducted to semiquantitatively assess MMP-20 expression in the DEJ, dentin-pulp complex components, and carious dentin. No apparent damage to the DEJ microstructure or other dentin-pulp complex components was observed and no statistically significant differences were detected in MMP-20 expression (p > 0.05) between the irradiated and control groups. This study rejected the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes. Hence, direct effects of radiation may not be regarded as an independent factor to explain aggressive clinical patterns of RRC.

The Significance of Matrix Metalloproteinases in Oral Diseases.

Matrix metalloproteinases (MMPs) belong to a family of structurally related zinc-dependent proteolytic enzymes that are known to play a key role in the catabolic turnover of extracellular matrix (ECM) components. Research studies to date have indicated that MMPs regulate the activity of several non-ECM bioactive substrates, including growth factors, cytokines, chemokines and cell receptors, which determine the tissue microenvironment. Disruption of the balance between the concentration of active matalloproteinases and their inhibitors (TIMPs) may lead to pathological changes associated with uncontrolled ECM turnover, tissue remodeling, inflammatory response, cell growth and migration. This brief review presents some information on MMPs' role in inflammatory, metabolic and cancer abnormalities related to the salivary glands, as well as MMP-related aspects that lead to the formation of human dentinal caries lesions. In oral diseases, the most relevant biological fluid commonly used for diagnosing periodontal diseases is saliva. In diseased patients with significantly higher levels of MMPs in their saliva than healthy people, most extracellular matrix components undergo digestion to lower molecular weight forms. Conventional treatment successfully reduces the levels of MMPs inhibits the progressive breakdown of gingival and periodontal ligament collagens. Beside inflammatory abnormalities like Sjögren's syndrome (SS), a large group of disorders is comprised of cancers, most of them involving the parotid gland.

Role of host-derived proteinases in dentine caries and erosion.

Demineralization in dentinal caries and erosion exposes dentine organic matrix. This exposed matrix, containing type I collagen and non-collagenous proteins, is then degraded by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. The knowledge of the identities and function of these enzymes in dentine has accumulated only within the last 15 years, but has already formed a field of research called 'dentine degradomics'. This research has demonstrated the role of endogenous collagenolytic enzymes in caries and erosion development. In demineralized dentine, the enzymes degrade triple-helical collagen molecules, leading to the gradual loss of collagen matrix. Even before that, they can cleave off the terminal non-helical ends of collagen molecules called telopeptides, leading to the structural changes at the intramolecular gap areas, which may affect or even prevent intrafibrillar remineralization, which is considered essential in restoring the dentine's mechanical properties. They may also cause the loss of non-collagenous proteins that could serve as nucleation sites for remineralization. Here we review the findings demonstrating that inhibition of salivary or dentine endogenous MMPs and cysteine cathepsins may provide preventive means against the progression of caries or erosion. Furthermore, we also suggest the future directions for the new experimental preventive research to gain more knowledge of the enzymes and their function during and after dentine demineralization, and the pathways to find the clinically acceptable means to prevent the functional activity of these enzymes.

Matrix metalloproteinases and other matrix proteinases in relation to cariology: the era of 'dentin degradomics'.

Dentin organic matrix, with type I collagen as the main component, is exposed after demineralization in dentinal caries, erosion or acidic conditioning during adhesive composite restorative treatment. This exposed matrix is prone to slow hydrolytic degradation by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. Here we review the recent findings demonstrating that inhibition of salivary or dentin endogenous collagenolytic enzymes may provide preventive means against progression of caries or erosion, just as they have been shown to retain the integrity and improve the longevity of resin composite filling bonding to dentin. This paper also presents the case that the organic matrix in caries-affected dentin may not be preserved as intact as previously considered. In partially demineralized dentin, MMPs and cysteine cathepsins with the ability to cleave off the terminal non-helical ends of collagen molecules (telopeptides) may lead to the gradual loss of intramolecular gap areas. This would seriously compromise the matrix ability for intrafibrillar remineralization, which is considered essential in restoring the dentin's mechanical properties. More detailed data of the enzymes responsible and their detailed function in dentin-destructive conditions may not only help to find new and better preventive means, but better preservation of demineralized dentin collagenous matrix may also facilitate true biological remineralization for the better restoration of tooth structural and mechanical integrity and mechanical properties.

Role of dentin MMPs in caries progression and bond stability.

Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This review will describe MMP functions in caries and hybrid layer degradation and explore the potential therapeutic role of MMP inhibitors for the development of improved intervention strategies for MMP-related oral diseases.

Caries-free subjects have high levels of urease and arginine deiminase activity

Objectives: This study investigated the relationship between urease and arginine deiminase system (ADS) activities and dental caries through a cross-sectional study. Material and Methods: Urease and ADS activities were measured in saliva and plaque samples from 10 caries-free subjects and 13 caries-active. Urease activity was obtained from the ammonia produced by incubation of plaque and saliva samples in urea. ADS activity was obtained from the ammonia generated by the arginine-HCl and Tris-maleate buffer. Specific activity was defined as micromoles of ammonia per minute per milligram of protein. Shapiro-Wilk statistical test was used to analyze the distribution of the data, and Mann-Whitney test was used to determine the significance of the data. Results: The specific urease activity in saliva and plaque was significantly higher in individuals with low DMFT scores. ADS activity in saliva (6.050 vs 1.350, p=0.0154) and plaque (8.830 vs 1.210, p=0.025) was also higher in individuals with low DMFT scores. Conclusions: Caries-free subjects had a higher ammonia generation activity by urease and arginine deiminase system for both saliva and plaque samples than low caries-active subjects. High levels of alkali production in oral environment were related to caries-free subjects. .

Abundance of MMPs and cysteine cathepsins in caries-affected dentin.

Degradation of dentin matrix components within caries dentin has been correlated with the activity of host-derived proteases, such as matrix metalloproteases (MMPs) and cysteine cathepsins (CTs). Since this relationship has not been fully established, we hypothesized that the abundance of MMPs and CTs in caries-affected dentin must be higher than in intact dentin. To test this premise, we obtained 5 slices (200 µm) from 5 intact teeth and from 5 caries-affected teeth (1 slice/tooth) and individually incubated them with primary antibodies for CT-B, CT-K, MMP-2, or MMP-9. Negative controls were incubated with pre-immune serum. Specimens were washed and re-incubated with the respective fluorescent secondary antibody. Collagen identification, attained by the autofluorescence capture technique, and protease localization were evaluated by multi-photon confocal microscopy. The images were analyzed with ZEN software, which also quantitatively measured the percentages of collagen and protease distribution in dentin compartments. The abundance of the test enzymes was markedly higher in caries-affected than in intact dentin. CT-B exhibited the highest percentage of co-localization with collagen, followed by MMP-9, MMP-2, and CT-K. The high expression of CTs and MMPs in caries-affected teeth indicates that those host-derived enzymes are intensely involved with caries progression.

Crystal structure of glucansucrase from the dental caries pathogen Streptococcus mutans.

Glucansucrase (GSase) from Streptococcus mutans is an essential agent in dental caries pathogenesis. Here, we report the crystal structure of S. mutans glycosyltransferase (GTF-SI), which synthesizes soluble and insoluble glucans and is a glycoside hydrolase (GH) family 70 GSase in the free enzyme form and in complex with acarbose and maltose. Resolution of the GTF-SI structure confirmed that the domain order of GTF-SI is circularly permuted as compared to that of GH family 13 α-amylases. As a result, domains A, B and IV of GTF-SI are each composed of two separate polypeptide chains. Structural comparison of GTF-SI and amylosucrase, which is closely related to GH family 13 amylases, indicated that the two enzymes share a similar transglycosylation mechanism via a glycosyl-enzyme intermediate in subsite -1. On the other hand, novel structural features were revealed in subsites +1 and +2 of GTF-SI. Trp517 provided the platform for glycosyl acceptor binding, while Tyr430, Asn481 and Ser589, which are conserved in family 70 enzymes but not in family 13 enzymes, comprised subsite +1. Based on the structure of GTF-SI and amino acid comparison of GTF-SI, GTF-I and GTF-S, Asp593 in GTF-SI appeared to be the most critical point for acceptor sugar orientation, influencing the transglycosylation specificity of GSases, that is, whether they produced insoluble glucan with α(1-3) glycosidic linkages or soluble glucan with α(1-6) linkages. The structural information derived from the current study should be extremely useful in the design of novel inhibitors that prevent the biofilm formation by GTF-SI.

Cysteine cathepsins in human carious dentin.

Matrix metalloproteinases (MMPs) are important in dentinal caries, and analysis of recent data demonstrates the presence of other collagen-degrading enzymes, cysteine cathepsins, in human dentin. This study aimed to examine the presence, source, and activity of cysteine cathepsins in human caries. Cathepsin B was detected with immunostaining. Saliva and dentin cysteine cathepsin and MMP activities on caries lesions were analyzed spectrofluorometrically. Immunostaining demonstrated stronger cathepsins B in carious than in healthy dentin. In carious dentin, cysteine cathepsin activity increased with increasing depth and age in chronic lesions, but decreased with age in active lesions. MMP activity decreased with age in both active and chronic lesions. Salivary MMP activities were higher in patients with active than chronic lesions and with increasing lesion depth, while cysteine cathepsin activities showed no differences. The results indicate that, along with MMPs, cysteine cathepsins are important, especially in active and deep caries.

Production of glucosyltransferase B and glucans by streptococcus mutans strains isolated from caries-free individuals

La glucosiltranferasa B es una enzima producida por Streptococcus mutans, que a partir de la sacarosa, cataliza la síntesis de glucanos insolubles los cuales dan soporte a la biopelícula, siendo uno de los principales factores de virulencia para la generación de la caries dental. Sin embargo, no se ha esclarecido su papel en los individuos libre de caries, portadores delmicroorganismo. El objetivo de este estudio fue determinar la producción de glucosiltransferasa B y la producción de glucanos por cepas de Streptococcus mutans aisladas de biopelícula de 30individuos libres de caries. Las cepas fueron cultivadas en caldo Todd Hewitt y las proteínas extracelulares fueron obtenidas por precipitación con sulfato de amonio las proteínas asociadas amembrana por extracción con urea. La presencia de GtfB fue determinada por peso molecular por SDS–PAGE, confirmada por Western Blot utilizando un anticuerpo específico y la producciónde polisacáridos por separación electroforética, incubación con sacarosa y coloración de Schiff. Los resultados muestran que el 96.7 por ciento de las cepas de Streptococcus mutans producen una banda a la altura del peso molecular correspondiente a las Gtf,de las cuales son reactivas por western blot el 63.4 por ciento El 93.3 por cientode las cepas producen polisacáridos. Conclusiones: la cepas de Streptococcus mutans aisladas de biopelícula de individuos sanos producen factores de virulencia asociados a la caries dental como glucosiltransferasa B y glucanos lo que indica que hay condiciones en la cavidad oral diferentes a estos factores que mantienen al individuo libre de caries dental, los cuales deben ser investigados en la búsqueda de estrategias para controlar la enfermedad.

Acción antimicrobiana in vitro de la miel de abejas sobre los microorganismos cariogénicos estreptococos del grupo mutans / In vitro antimicrobial activity of honey on mutans streptococci

En el presente estudio fue evaluada la actividad antimicrobiana in vitro de cuatro muestras de mieles producidas en nuestro país, sobre los recuentos de estreptococos del grupo mutans, en escolares con alto riesgo de caries dental. Se obtuvieron muestras de saliva de 20 escolares, con edades entre 12 y 14 años, pertenecientes a la ciudad de Temuco, Región de La Araucanía (Chile). El recuento de estreptococos del grupo mutans en saliva fue estimado por el método microbiológico semi-cuantitativo Linoscreen®. La evaluación de la acción antibacteriana de la miel se realizó en 9 escolares que presentaron los recuentos más elevados de estreptococos del grupo mutans, utilizando concentraciones de miel entre 5 por ciento y 35 por ciento. Los datos mostraron que el 100 por ciento de los niños analizados poseían colonias de estreptococos del grupo mutans en su saliva. Además, se verificó que el 45 por ciento (9/20) de los escolares se encontraba en la categoría de alta actividad cariogénica. Con este estudio, también se comprobó que la miel de abejas posee actividad antimicrobiana sobre las bacterias estreptococos del grupo mutans y que no existían diferencias significativas entre las 4 mieles utilizadas, con relación a su capacidad antibacteriana (p>0.05). Por otra parte, este estudio también permitió demostrar que a mayor concentración de miel utilizada mayor era la reducción de las bacterias cariogénicas. En conclusión, en el presente estudio se demostró la acción antimicrobiana in vitro de la miel sobre los recuentos de bacterias cariogénicas estreptococos del grupo mutans. Sin embargo, serán necesarios futuros estudios para identificar y evaluar los componentes de la miel de abejas, responsables de esta propiedad.

The aim of the present issue was to evaluate the antibacterial activity of four commercial honeys against mutans streptococci in schoolchildren with high risk of caries development. We have investigated 20 schoolchildren from Temuco city (Chile), aged 12 -14 years. Saliva samples were obtained by stimulation with solid paraffin. The count of mutans streptococci in saliva was estimated by microbiological method. The antimicrobial activity of honey was evaluated by dilution in TYCBS medium in 9 schoolchildren (> 500.000 cfu/mL). Four concentrations of honey were used ranging from 5 to 35 percent. The presence of S. mutans was detected in 100 percent of schoolchildren. Our data shown that honey present high antimicrobial activity against S. mutans, being the dilutions at 30 and 35 percent that shown the better inhibitory effect (p<0.001). No differences between 4 honeys in relation to antibacterial activity were observed (p>0.05). In conclusion, our data showed that honeybees present in vitro antibacterial activity against S. mutans. However, future studies are necessary to characterize the honey components, responsible for this property.

Inorganic chemistry of defensive peroxidases in the human oral cavity.

The innate host response system is comprised of various mechanisms for orchestrating host response to microbial infection of the oral cavity. The heterogeneity of the oral cavity and the associated microenvironments that are produced give rise to different chemistries that affect the innate defense system. One focus of this review is on how these spatial differences influence the two major defensive peroxidases of the oral cavity, salivary peroxidase (SPO) and myeloperoxidase (MPO). With hydrogen peroxide (H(2)O(2)) as an oxidant, the defensive peroxidases use inorganic ions to produce antimicrobials that are generally more effective than H(2)O(2) itself. The concentrations of the inorganic substrates are different in saliva vs. gingival crevicular fluid (GCF). Thus, in the supragingival regime, SPO and MPO work in unison for the exclusive production of hypothiocyanite (OSCN(-), a reactive inorganic species), which constantly bathes nascent plaques. In contrast, MPO is introduced to the GCF during inflammatory response, and in that environment it is capable of producing hypochlorite (OCl(-)), a chemically more powerful oxidant that is implicated in host tissue damage. A second focus of this review is on inter-person variation that may contribute to different peroxidase function. Many of these differences are attributed to dietary or smoking practices that alter the concentrations of relevant inorganic species in the oral cavity (e.g.: fluoride, F(-); cyanide, CN(-); cyanate, OCN(-); thiocyanate, SCN(-); and nitrate, NO(3)(-)). Because of the complexity of the host and microflora biology and the associated chemistry, it is difficult to establish the significance of the human peroxidase systems during the pathogenesis of oral diseases. The problem is particularly complex with respect to the gingival sulcus and periodontal pockets (where the very different defensive stratagems of GCF and saliva co-mingle). Despite this complexity, intriguing in vitro and in vivo studies are reviewed here that reveal the interplay between peroxidase function and associated inorganic chemistry.

The role of matrix metalloproteinases in the oral environment.

This review focuses specifically on matrix metalloproteinases (MMPs) and their role in physiological and pathological extracellular matrix (ECM) remodeling and degradation processes in the oral environment. A group of enzymes capable of degrading almost all ECM proteins, MMPs contribute to both normal and pathological tissue remodeling. The expression of different MMPs may be upregulated in pathological conditions such as inflammation and tumor invasion. The balance between activated MMPs and tissue inhibitors of metalloproteinases (TIMPs) controls the extent of ECM remodeling. Prior to mineralization, MMPs may participate in the organization of enamel and dentin organic matrix, or they may regulate mineralization by controlling the proteoglycan turnover. There is evidence indicating that MMPs could be involved in the etiology of enamel fluorosis and amelogenesis imperfecta. They seem to play a part in dentinal caries progression, since they have a crucial role in dentin collagen breakdown in caries lesions. MMPs have been identified in pulpal and periapical inflammation and are strongly correlated with periodontal diseases, since they are the major players in collagen breakdown during periodontal tissue destruction. The use of MMP inhibitors could help the prevention and treatment of many MMP-related oral diseases.

Matrix metalloproteinases (MMPs) in oral diseases.

Matrix metalloproteinases (MMPs) are a group of enzymes that in concert are responsible for the degradation of most extracellular matrix proteins during organogenesis, growth and normal tissue turnover. The expression and activity of MMPs in adult tissues is normally quite low, but increases significantly in various pathological conditions that may lead into unwanted tissue destruction, such as inflammatory diseases, tumour growth and metastasis. MMPs have a marked role also in tissue destructive oral diseases. The role of collagenases, especially MMP-8, in periodontitis and peri-implantitis is the best-known example of the unwanted tissue destruction related to increased presence and activity of MMPs at the site of disease, but evidence has been brought forward to indicate that MMPs may be involved also in other oral diseases, such as dental caries and oral cancer. This brief review describes some of the history, the current status and the future aspects of the work mainly of our research groups looking at the presence and activity of various MMPs in different oral diseases, as well as some of the MMP-related aspects that may facilitate the development of new means of diagnosis and treatment of oral diseases.

[The activities of proteolytic enzymes in dental plaque of patients in different age-sex groups].

This study was intended to explore the relationship between the proteolytic enzymes in dental plaque and the patient's age and sex. Fluorometry and spectrometry were used to separately determine the activities of leucine amino peptidase, dipeptidyl peptidase IV and trypsin-like proteinase in children(10 boys and 10 girls), adults(n = 20) and elderly people(n = 10). The results showed that sex almost had no influence on the activities of the three enzymes in dental plaque in the children(P > 0.05), and with the increase of age, the activities of the three enzymes apparently increased (P < 0.01). These findings imply that the proteolytic enzymes may only play important roles in root lesions.

[A primary study of relationship between proteolytic enzymes in dental plaque and deciduous caries].

OBJECTIVE: The purpose of this paper was to study the role of proteolytic enzymes in dental plaque in deciduous caries occurrence. METHODS: Fluorometry and spectrometry were used separately to determine the activities of leucine amino peptidase, dipeptidyl peptidase IV and trypsin-like proteinase in caries-positive and caries-free children. RESULTS: The activities of the three enzymes in dental plaque in different children were same (P > 0.05). CONCLUSION: The three enzymes may be not related to deciduous caries.

[The study of the activities of salivary proteolytic enzymes in children].

OBJECTIVE: The activities of proteolytic enzymes in saliva were assayed to determine whether they were related to caries sensitivity and gender in the children. METHODS: Fluorometric and photometric methods were applied. Three enzymes included leucine amino peptidase, dipeptidyl peptidase IV and trypsin-like proteinase. RESULTS: 1. Only dipeptidyl peptidase IV and trypsin-like proteinase were demonstrated in saliva, they were obviously lower than those in dental plaque (P < 0.05); 2. The activities of proteolytic enzymes of male and female children as well as caries-active and caries-free children showed no difference. CONCLUSION: Proteolytic enzymes play little role in caries formation of deciduous tooth.

An immunohistochemical study of HLA-DR and alpha 1-antichymotrypsin-positive cells in the pulp of human non-carious and carious teeth.

The condition of the pulp tissue was classified into seven groups according to the progression of carious lesions from stages S0 (non-carious teeth) to S6 (exposed pulp). There was a small number of anti-HLA-DR antibody-positive cells in the pulp of the early carious teeth, and a markedly increased number at S5 and S6. The recruitment of a large number of anti-HLA-DR cells concomitant with a marked increase of other kinds of immunocompetent cells in the pulp of late-stage caries might indicate the occurrence of antigen presentation followed by both cell-mediated and humoral immune reactions. The number of anti-alpha 1-antichymotrypsin (ACT) antibody-positive macrophages showed a proportional increase with the development of caries, and these cells may be involved in protecting against the tissue damage caused by proteases released from inflammatory cells, as well as having a defensive role by phagocytosis of toxic micro-organisms and damaged tissue residues. Thus anti-HLA-DR and anti-ACT antibody-positive cells might participate in both an efficient immune system and a tissue-protective mechanism in the human dental pulp.