280 volume 2 • issue 4 October / December 2012 • pp. 280-284

C. Giuroiu, Maria Vataman, Liana Aminov, Mihaela Sălceanu, S. Andrian

AbstractThe present study aimed at assesssing – by clinical,

histological and radiological investigations – the influence of some external factors on the pulp-dentin complex, and at providing a causal interpretation of the structural changes observed.

Materials and methods. Clinical and radiological exams were performed on 65 old patients with ages between 60-75, and also on 40 young patients with ages between 20-35, presenting different dental-periodontal pathologies. The pulp-dentin complex was submitted to a morphopathological examination, to highlight the struc-tural changes observed at microscopic level. Fragments of dental pulp were imersed in a 4% formaldehyde solution with phosphate buffer 0.1 M., pH 7.2, for 12 -14 hours, at a temperature of 4ºC, and 3-5 µm thick slices were prepared. The slices were coloured with hematoxylin-eosine (HE), by the trichromic technique – Masson. Photographies were takenwithaZeissmicroscope,withKodak200ASA.

Results. Significant differences were observed, between the two groups of patients, as to the external factors that produce structural changes on pulp-dentin organ. In the group of young patients dental caries and coronal fillings prevailed, while the group of old patients was mostly asso-ciated with atrition and chronic marginal periodontitis. Out of the 40 young patients, 30 presented chronic dental caries (75%), while, among the 65 old patients, only 24 pre-sented dental caries (36.9%). The percentages of coronary fillings between the two study groups were close, which could be considered as one of the causes producing changes in the pulp-dentin organ, following aggresive preparation of cavities, the action of materials used for the protection of pulp-dentin complex or of the materials used for cor-onry fillings.

Conclusions. Dental pulp has a remarkable ability to counteract the action of harmful factors, producing a min-eral barrier and stimulating the reparatory processes. Changes in the endodontic space can be produced in both experimental groups, but more intensely and more fre-quently in the old patients. The endodontic space is mod-ified, both physiologically and pathologically, including deposition of secondary or tertiary dentin (reactionary or reparative dentin), as well as pulp reactions, such as: inflammation, fibrosis, calcium degeneration or vacuolisis. At cell level, microsocopic images showed a decrease of the odontoblasts number and sizes, as well as a reduced

fibroblasts/fibrocytes ratios. These changes are associated with progressive vascular and nervous changes, that can be considered both theis cause and effect. These patho-logical transformations are related with a more difficult preparation of the endodontic space and can be considered as having a major role in the failure of endodontic therapy.

Keywords: pulp-dentin complex, atrition, coronal filling, chronic marginal periodontitis, dental caries.

INTRODUCTION

The pulp-dentin complex suffers multiple influences of some external factors, more or less aggresive, provoking a pulp tissues reaction associated with various structural and functional changes. The normal reactions of the pulp-dentin complex, under the influence of termal changes or of slow dental abrasion, are represented by deposition of secondary dentin.

Secondary dentin is the newly formed dentin during dental eruption, after its eruption and after the end of apexification process. Secondary dentin is formed continuously as a regular uni-form layer around pulp cavity, at a very low rate. It has the chemical composition of an anorganic and organic material, similar with primary den-tin, ye differentiated by some characteristics [1]. As to the pathological changes, they are pro-duced under the influence of more aggresive fac-tors, that interfere with the normal activity of the pulp-dentin complex, determining various reac-tions, that may cause the loss of pulp vitality. Among these factors, mention should be made of: treatments of dental caries, the action of restorative materials, atrition and chronic mar-ginal periodotitis.

The reaction of pulp to these factors differs as to nature, intensity, action time, being expressed

CLINICAL, HISTOLOGICAL AND RADIOLOGICAL ASPECTS REGARDING THE INFLUENCE OF SOME EXTERNAL FACTORS ON

THE PULP-DENTIN COMPLEX

C. Giuroiu1, Maria Vataman2, Liana Aminov3, Mihaela Sălceanu3, S. Andrian2

1. PhDStudent,Dept.Odontology,FacultyofDentalMedicine“Gr.T.Popa”U.M.Ph.,Iaşi2. Prof.,PhD,Dept.Odontology,FacultyofDentalMedicine”Gr.T.Popa”UM.Ph.,Iaşi3. Assist.Prof.,PhD,Dept.Odontology,FacultyofDentalMedicine”Gr.T.Popa”UM.Ph.,IaşiContact person: Giuroiu Cristian, e-mail: giuroiu.cristian@yahoo.com

Endodontics

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CLINICAL, HISTOLOGICAL AND RADIOLOGICAL ASPECTS REGARDING THE INFLUENCE OF SOME EXTERNAL FACTORS ON THE PULP-DENTIN COMPLEX

as deposition of tertiary dentine (reactionary dentin, or reparatory dentin) [2,3], or as mild/severe pulp inflammation. In cases with severe aggresion, the function of destroying odonto-blasts is assumed by the “odontoblast–like” cells, represented by undifferentiated mesenchimal cells or even by fibroblasts, that produce repara-tory dentin [4, 5]. The deposition model and the dimensions of the new tertiary dentin area are correlated with the intensity and action period of the harmful/aggresive agent. When the inten-sity (nature) of the aggresion factors is only mod-erate, the surviving odontoblasts can synthetize the reactionary dentin, with a structure similar to primary dentine [6].

Under the influence of the aggresive factors, pulp tissues suffer multiple structural changes, the most frequent causes being represented by accute or chronic inflammatory processes, asso-ciated with a series of characteristic pathological phenomena. These changes can induce necrosis, fibrosis, mineralising dystrophy, being associ-ated with denticles or pulp calculus.

Dental pulp also tries to stop the evolution of the carious process through remineralisation of dental demineralised matrice and dentine scle-rosis [7]. At dentin level, the presence of dentinal tubules, as well as a lower content of minerals and the cristalisation process, allow a more rapid evolution of dental caries [8]. When the high intensity of the aggresive factors is combined with the absence of therapeutical measures, the odontoblasts suffer destructive processes. Inside the pulp-dentine complex, a defensive layer is formed by the mobilisation of PMN, lym phocites, macrophages, plasmocites, along with induction of an immune response and formation of a fibro-sis tissue barrier following a more increased activity of fibroblasts, with the final aim to iso-late the inflammatory area by the healthy pulp tissue [9]. Pulp ageing is associated with a high degree of “physiological ageing”, morphological and functional changes, and progressive deterio-ration [10]. The periodontal recessions associated to ageing or to marginal periodontal diseases, expose the cement-enamel jonction to the aggresive factors of the oral environment [11]. The attachment loss represents the sum of the two types of visible and invisible recession [12].

MATERIALS AND METHOD

Clinical and radiological exams were per-formed on 65 old patients with ages between 60-75 years, and also on 40 young patients with ages between 20-35 years, presenting different dental-periodontal pathologies. The pulp-dentin complex was submitted to morphopathological exam, to highlight the structural changes pro-duced at microscopic level. The dental pulp frag-ments were immersed in a 4% formaldehyde solution with phosphate buffer 0.1 M., pH 7.2, for 12 -14 hours, at 4ºC. 3-5 µm thick slices were prepared.

The slices were coloured with hematoxylin-eosine (HE) and by the tricromic technique-Mas-son. The examination and photographies were performedusingaZeissmicroscope,withKodak200 ASA.

RESULTS AND DISCUSSION

Between the two groups of patients significant differences were observed regarding the external factors that produce structural changes on the pulp-dentin organ. In the experimental group of young patients, dental caries and coronal fillings prevailed, while the group of old patients was mostly associated with atrition and chronic mar-ginal periodontitis. Out of the 40 young patients, 30 presented chronic dental caries (75%) while, out of the 65 old patients, only 24 presented den-tal caries (36.9%). This aspect highlights the fact that young patients have a higher prevalence of dental carious disease with more rapid evolution to accute pulp inflammation. For old patients, the evolution of dental caries is slower, because of the continuous deposition of secondary dentin along pulp room walls. The percentages of coro-nal fillings between the two groups were close, which could be a cause of the changes observed in the pulp-dentin organ, following aggresive preparation of cavities, the action of materials used for the protection of pulp-dentin complex or materials used for coronal fillings. Higher per-cents of pulp-dentin organ changes were found in old patients, presenting atrition or chronic marginal periodontitis, as a result of local inflam-matory factors and accentuated hard tissues loss.

282 volume 2 • issue 4 October / December 2012 • pp. 280-284

C. Giuroiu, Maria Vataman, Liana Aminov, Mihaela Sălceanu, S. Andrian

Fig. 1. Possible causes of pulp-dentin complex structural changes in males

Fig. 2. Possible causes of pulp-dentin complex structural changes for females

The data presented in figure 1 confirm that multiple aggresions (physical, mechanical, ther-mal), exerted on long-term periods, are associ-ated with secondary or tertiary dentin deposition following the activity of pulp odontoblasts.

Fig. 3. Maxillary molars with chronic marginal periodontitis and incipient proximal dental caries, associated with significant decreases of pulp room after deposition of secondary and tertiary dentin

Dentin depositions (fig. 3) prevailing at the level of pulp horns, determine retraction of pulp room roof, sometimes followed by pulp room disappearance. Decrease of pulp room volume or even pulp room disappearance lead to more difficult endodontic treatments, especially for beginner dental practitioners.

For multiroot teeth, the furcation area is fre-quently associated with dentin deposition, hav-ing unfavourable effect on the access of root canals, as well as on the mechanico-chemical stage of the endodontic treatment, as evidenced by the radiographical image of a maxillary molar in an old patient. The external aggresions exerted along years, represented by deep proximal decay and an inflammatory periodontal process, were followed by modification of endodontic space anatomy (fig. 4).

Fig. 4. Tooth 2.6. with chronic marginal periodontitis, associated with tertiary dentin deposition especially

in the furcation area

Fig. 5. Tooth 3.6., with a deep carious process, restored with composite resin, presents significant retraction of both pulp horns and pulp room roof

Coronal fillings represent another factor asso-ciated with the modification of endodontic space anatomy. Aggresive instrumentation performed

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CLINICAL, HISTOLOGICAL AND RADIOLOGICAL ASPECTS REGARDING THE INFLUENCE OF SOME EXTERNAL FACTORS ON THE PULP-DENTIN COMPLEX

for cavity preparation and filling, as well as cor-onal restorative materials represent harmful fac-tors that can provoke the deposition of successive dentin layers, as shown by the radiographical image of 3.6. (fig. 5).

The next radiological image (fig. 6) allowed the identification of an endodontic space with significant radioopacity at 4.4., both in coronal third and apical third of root canal, which makes more difficult the mechanical preparation during the endodontic treatment. Tooth 4.3. also pre-sents a pulp calculus in the coronal third of the root canal.

Fig. 6. Pulp calcifications can be unique,

multiple to the same tooth (4.4.) or to multiple teeth, at the same patient

To highlight such pulp changes, pulp frag-

ments were sampled and processed for micro-scopic examinations, from the teeth with severe pulp inflammations. In young patients, struc-tural changes of pulp were localised only in areas associated with inflammations produced by deep dental caries or after aggresive prosthetic preparation of the dental structure. In the case of a tooth with deep distal-occlusal decay, micro-scopic image shows a discrete disorganisation of the odontoblastic layer, slight oedema of the extracellular matrix and the presence of star-shaped fibroblasts (fig. 7).

Fig. 7. Incipient pulp inflamation

The next figure presents the histological aspects of a tooth with open ulcerative pulpitis associated with the presence of lymphocites, plasmocites, macrophages, dilated vessels, sta-sis, interstitial oedema (fig. 8).

Fig. 8. Chronic inflamation of pulp tissue

In old patients, the modifications are more various and complex. The following figure plots the histological aspect of a pulp sample from a tooth with intense atrition and a chronic inflam-matory process. The image shows an area with pulp fibrosis and inflammatory oedema (Fig. 9).

Fig. 9. Fibrosis process of pulp tissue

The next image shows a pulpal area present-ing a vacuolisis degenerative process, with oval-shaped or polyhedral-shaped white adipocytes (fig. 10).

Fig. 10. Pulp degeneration (vacuolisis)

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C. Giuroiu, Maria Vataman, Liana Aminov, Mihaela Sălceanu, S. Andrian

Another pulp reaction, seen at a tooth with chronic marginal periodontitis and atrition, is represented by the mineralisation areas appear-ing between the collagen fascicles. The odonto-blastic layer is well-represented, while the rest of pulp contains more fibrocytes than fibroblasts (fig. 11).

Fig. 11. Incipient pulp mineralisation

CONCLUSIONS

Our research approached aspects regarding structural changes of the pulp-dentin complex, initiated by different external stimulus. To dif-ferentiate the effects of these stimuli, as to their nature, intensity and duration, two experimental groups, of young (20-35 years) and, respectively, old patients (60-75 years), were investigated by clinical, radiological and histological examina-tions.

We have focused on the pulp-dentin complex changes and on the defence pulp reactions, fol-lowing the action of some external aggresive fac-tors. The microscopic images showed the remarkable ability of pulp to oppose to the action of the harmful factors, producing mineral barri-ers and stimulating the repair process. The causes of these changes in the pulp-dentin complex were: dental caries, coronal fillings, chronic mar-ginal periodontitis and atrition.

Modifications in the endodontic space can be produced in both groups, being however more intense and more frequently occurring in old patients. The nature and intensity of these reac-tions differ among patients and teeth, highlight-ing the influence of the individual, genetically transmitted features. The endodontic space, both

physiological and pathological modifications, included deposition of secondary or tertiary den-tin (reactionary dentin or reparative dentin), as well as pulp reactions, such as: inflammation, fibrosis, calcium degeneration or vacuolisis. At cellular level, the microsocopic images showed a decrease of the odontoblasts number and size, as well as reduction of the fibroblasts/fibrocytes ratio. These changes are associated with progres-sive vascular and nervous modifications, that can be considered simultaneously a cause and an effect. These pathological transformations, related with a more difficult preparation of the endodontic space, can be considered a major cause in the failure of endodontic therapy.

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