Dentin sialoprotein and dentin phosphoprotein have distinct roles in dentin mineralization

Dentin sialophosphoprotein (DSPP), a major non-collagenous matrix protein of odontoblasts, is proteolytically cleaved into dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Our previous studies revealed that DSPP null mice display a phenotype similar to human autosomal dominant dentinogenesis imperfecta, in which teeth have widened predentin and irregular dentin mineralization resulting in sporadic unmineralized areas in dentin and frequent pulp exposure. Earlier in vitro studies suggested that DPP, but not DSP, plays a significant role in initiation and maturation of dentin mineralization. However, the precise in vivo roles of DSP and DPP are far from clear. Here we report the generation of DPPcKO mice, in which only DSP is expressed in a DSPP null background, resulting in a conditional DPP knockout. DPPcKO teeth show a partial rescue of the DSPP null phenotype with the restored predentin width, an absence of irregular unmineralized areas in dentin, and less frequent pulp exposure. Micro-computed tomography (micro-CT) analysis of DPPcKO molars further confirmed this partial rescue with a significant recovery in the dentin volume, but not in the dentin mineral density. These results indicate distinct roles of DSP and DPP in dentin mineralization, with DSP regulating initiation of dentin mineralization, and DPP being involved in the maturation of mineralized dentin.

Pulpal response to cavity preparation by an erbium, chromium:YSGG laser-powered hydrokinetic system

The near red-pulsed erbium, chromium:yttrium-scandium-gallium-garnet laser hydrokinetic system, or Er,Cr:YSGG laser HKS, is effective in cutting dental hard tissues. In this longitudinal study, the authors studied the continuously erupting open-apex incisors of New Zealand albino rabbits and the constricted apex teeth of beagles to determine the effects of HKS-produced lesions at various energy levels and of preparations produced by a tapered fissure bur on dental pulp. No pulpal inflammatory responses could be identified either immediately or 30 days after surgery in HKS preparations that removed enamel and dentin without pulp exposure.

Immunohistochemical study on the immunocompetent cells of the pulp in human non-carious and carious teeth

The condition of the pulp tissue was classified into seven groups according to the depth of carious lesions from stage (S) 0 (non-carious teeth) to S6 (exposed pulp). A substantial change in the infiltration of immunocompetent cells occurred between S3 and S4; all types were markedly increased in S4 as compared to S3, with a remarkable increase in the number of helper T lymphocytes, B-lineage cells, neutrophils and macrophages. Therefore, the pulpal immune reaction to carious stimuli could be classified into early (S1-S3) and advanced phases (S4-S6). In the early phase a cellular immunoresponse would be induced by T-lineage cells, and in the advanced phase the humoral immunoresponse is furthered by B-lineage cells concomitant with the destruction of pulp tissue by proteolytic enzymes released from infiltrating neutrophils and macrophages. Human dental pulp is thus equipped with a functional immune response that is sufficient as a biodefensive mechanism. Dental caries should be treated before S4.

Vital pulp therapy in cariously exposed permanent teeth and its limitations

Vital pulp therapy for cariously exposed permanent teeth remains one of the most controversial areas in dentistry. Because a vital, functioning pulp is capable of initiating several defence mechanisms to protect the body from bacterial invasion, it is beneficial to preserve the vitality and health of an exposed pulp rather than replace it with a root filling material following pulp exposure. There is no consensus on the survival rate of formerly cariously exposed pulps. Observation time, judgement criteria, pulpotomy/pulp capping technique and, most importantly, pulpal status at the time of treatment, vary to a great extent amongst studies. In mature teeth, a pulp exposed by caries is usually removed and the root canals are cleaned, shaped and filled. Amongst the methods for preservation of a cariously exposed pulp, partial pulpotomy has yielded a markedly high success rate in young teeth. Major limitations in the success of vital pulp therapy in cariously exposed permanent teeth exist. The lack of predictability and long-term success greatly influence decision-making. The decision-making itself is unreliable primarily due to the difficulty of accurately diagnosing the ability of the pulp to repair. While there are indications for vital pulp therapy in young permanent molars, it must be remembered that ultimately, none of these procedures enjoy the long-term success of complete root canal therapy.

Production of amelogenin by enamel epithelium of Hertwig's root sheath

OBJECTIVE

To study the multiple potentials of differentiating odontogenic epithelial cells.

STUDY DESIGN

Bilateral first and second maxillary molars of 30 immature rats were perforated into the pulp chambers with a round bur. The pulps were observed histologically and immunohistochemically for amelogenin 3, 7, and 14 days after the perforation.

RESULTS

On day 7, the enamel epithelium of Hertwig's root sheath migrated and formed oval-shaped epithelial islands that resembled epithelial rests of Malassez. On day 14, the islands consisted of epithelial cells with large nuclei and cytoplasm partially surrounded by a subsequently formed osteodentin and cementum. Immunoreactivity for amelogenin was observed in the large epithelial cells and in the area between the cells as well as the calcified tissues. Some of the enamel epithelium resembling columnar ameloblasts of the enamel organ were also positive for amelogenin.

CONCLUSIONS

The enamel epithelium of Hertwig's root sheath appeared to differentiate into ameloblasts and produce amelogenin.

Biological response of pulps submitted to different capping materials

Pulp capping is a procedure that comprises adequate protection of the pulp tissue exposed to the oral environment, aiming at the preservation of its vitality and functions. This study evaluated the response of the dental pulps of dog teeth to capping with mineral trioxide aggregate (MTA) or calcium hydroxide P.A. For that purpose, 37 teeth were divided into two groups, according to the capping material employed. Two dogs were anesthetized and, after placement of a rubber dam, their pulps were exposed in a standardized manner and protected with the experimental capping materials. The cavities were then sealed with resin-modified glass ionomer cement and restored with composite resin. After sixty days, the animals were killed and the specimens were processed in order to be analyzed with optic microscopy. It was observed that MTA presented a higher success rate compared to calcium hydroxide, presenting a lower occurrence of infection and pulp necrosis.

Randomized controlled clinical trial of the 24-months survival of composite resin restorations after one-step incomplete and complete excavation on primary teeth

OBJECTIVE

This randomized clinical trial aimed to compare the 24-months survival of composite restorations in primary molars after partial caries removal (PCR) and total caries removal (TCR).

METHODS

Forty-eight children aged 3-8 years with at least one molar with a deep carious lesion were included (PCR; n=66; TCR; n=54). For PCR, excavation was stopped when dentine with a leathery consistency was achieved; in the TCR group, total absence of carious tissue was confirmed using a blunt-tipped probe. Pulpotomy was performed in cases of pulp exposure. Success was assessed by modified USPHS criteria with Alpha and Bravo scores recorded as success.

RESULTS

Pulp exposure occurred in 1 and 15 of the teeth treated with PCR and TCR respectively (p<0.01). The restorations survival rate after 24 months was 66% (PCR) and 86% (TCR) (p=0.03). When teeth that received pulpotomy were analyzed separately, the survival rate was 92% (p=0.09). PCR performed in occlusoproximal restorations demonstrated the lowest success rate (p=0.002). PCR increases 2.90 times the probability of having a restorative failure compared to TCR (p=0.03), after adjusting for cavity type. When pulp exposure and restoration failure were considered as the outcome, there was no significant difference between the two groups (p=0.10) with success rates of 64% (PCR) and 61% (TCR).

CONCLUSION

Collectively, deciduous teeth submitted to PCR prevented pulp exposure and, consequently, more invasive treatments; otherwise, PCR yielded lower longevity for composite restoration compared to TCR, suggesting that PCR restorations need to be followed over time, especially when multi-surface restorations are involved.

CLINICAL SIGNIFICANCE

Composite restorations on carious remaining tissue require monitoring over time, especially those performed in more than one surface. Even if the restorations present shortcomings over the time, the majority of them are subject to repair, allowing more conservative approaches for teeth with deep caries lesions.

Formation of dentin-like particles in dentin defects above exposed pulp by controlled release of fibroblast growth factor 2 from gelatin hydrogels

The induction of dentin formation on exposed dental pulp is a major challenge in research on the regeneration of the dentin-pulp complex. We examined the effects of fibroblast growth factor 2 (FGF2), which was delivered in either a collagen sponge (noncontrolled release) or incorporated into gelatin hydrogels (controlled release), on the formation of dentin in exposed rat molar pulps. During the early phase of pulp wound healing, pulp cell proliferation and invasion of vessels into dentin defects above exposed pulp were induced in both groups. In the late phase, the induction of dentin formation was distinctly different between the 2 types of FGF2 release. The noncontrolled release of free FGF2 from collagen sponge induced excessive reparative dentin formation in the residual dental pulp, although dentin defects were not noted. In contrast, controlled release of FGF2 from gelatin hydrogels induced the formation of dentin-like particles with dentin defects above exposed pulp. These results suggest the possibility of a novel therapeutic approach for dentin-pulp complex by controlled release of bioactive FGF2.

Primary molar pulp therapy--histological evaluation of failure

OBJECTIVES

Qualitative comparison of the clinical, radiographic and histological outcomes in a small sample of cariously exposed primary molars, extracted after unsuccessful pulp treatment by two vital pulpotomy methods.

SUBJECTS AND METHODS

The primary molars were extracted, because of treatment failure, during a longitudinal clinical investigation of the relative efficacy of 20% Buckley's Formocresol versus calcium hydroxide powder as pulp dressings in vital pulp therapy (in press). Fifty-two child patients were sequentially enrolled in the longitudinal clinical investigation, 26 boys and 26 girls. Primary molar teeth requiring vital pulp therapy were randomly allocated to either the formocresol group (F) or the calcium hydroxide group (C). Coronal pulp amputation was prescribed only in teeth with vital, cariously-exposed pulp tissue. All cases were reviewed using predefined clinical and radiological criteria. Seventy-nine cariously-exposed primary molars required vital pulp therapy. Forty-four teeth were included in group F and 35 in group C. Five per cent (n = 2) of teeth in group F and 11 per cent of teeth (n = 4) in group C were terminated from the trial due to clinical and/or radiographic failure. Of the six teeth extracted, five were sufficiently intact to be retained for histological evaluation.

RESULTS

Post-extraction radiographs taken before specimen preparation showed reactionary dentine barrier (bridge) formation in teeth treated with calcium hydroxide. However, the narrowing of root canals, indicative of appositional reactionary dentine deposition, was seen in both groups (F and C). Histological examination confirmed these findings and revealed that pus cells were evident in all specimens examined. There was also histological evidence of resorption of reactionary dentine within the root canal and that forming the calcified barrier (dentine bridge).

CONCLUSION

The clinical and radiographic outcomes for the five teeth correlate well with the reported findings from decalcified histological section. Although numbers are small, the histological findings may indicate possible reasons for treatment failure. There are few reports of this sort in the literature of this under-researched treatment modality.

IL-1 alpha and TNF-alpha expression in early periapical lesions of normal and immunodeficient mice

T-helper and B-lymphocytes may contribute to mechanisms that result in bone-resorptive cytokine production in periapical lesion. Mice with severe combined immunodeficiency (scid) lack functional B- and T-cell immunity. The purpose of this study was to investigate the progression of pulp necrosis and the histomorphometric features of periapical lesions in scid vs. normal mice. The expression of the bone-resorptive cytokines IL-1 alpha and TNF-alpha was also investigated. Sixteen five-week-old homozygous scid mice and 14 normal BALB/cJ mice were used. The pulps of mandibular first molars were exposed for 1, 2, 3, or 4 weeks. Blocks of tissue containing the mandibular teeth and supporting structures were processed for both light microscopic examination and immunohistochemical staining for IL-1 alpha dna TNF-alpha. Central sections were randomized, their images were blindly digitized into a computer, and the areas of the lesions surrounding the distal root apices were measured. The cells that stained positively for the cytokines in the same area of adjacent sections were counted. Pulp necrosis progressed at similar rates in teeth from both strains. A progressive and significant increase in the periapical lesion size in both strains was observed. The scid mice lesions were significantly smaller than the controls at only the three-week period. There was heavy cytokine staining in periapical lesions from both strains, especially in areas that contained a mixed inflammatory infiltrate or fibroblasts. The number of positively staining cells was proportional to the lesion size. Therefore, pulpal and periapical pathosis were independent of the presence of functional T- and B-cells in this model.

Histopathological evaluation of the dental pulps in crown-fractured teeth

Trauma is a common cause of pulpal damage. In traumatic injuries, the first priority is to protect the vitality of pulps. But the time between the trauma and treatment must be short to preserve vital, noninflamed pulps. The aim of this study was to investigate the histopathological changes in pulpal tissues at different time periods after crown fractures. Twenty-three teeth with enamel and dentin fractures, with and without pulp exposure were evaluated. The reasons for seeking dental treatment were aesthetic consideration, pain, or discomfort. The extirpated pulps were histologically prepared for microscopical evaluation. There was myelin degeneration surrounding the axons and edema in the early posttraumatic stages (17 h). In the later stages (4 to 20 days), the tissues showed varying degrees of inflammation, and neuronal degeneration such as intramyelin edema, aberrant myelin synthesis, and axonal swelling.

Appearance of neuropeptide Y-like immunoreactive cells in the rat trigeminal ganglion following dental injuries

The effects of these injuries on the presence and distribution of neuropeptide Y (NPY)-immunoreactive (-IR) neurones were examined immunohistochemically. In the normal trigeminal ganglion: some perivascular nerves displayed NPY-IR but there were no NPY-IR ganglionic cells. Fourteen days after extraction or pulp exposure of the upper first molar, NPY-IR cells appeared in the maxillary region of the trigeminal ganglion. About 90% of the injury-evoked NPY-IR cells had medium to large diameters (more than 300 microns2 in cross-sectional area). Shallow cavity preparation, however, did not induce the appearance of NPY-IR cells in the trigeminal ganglion. These results indicate the dental injuries alter the primary sensory neurones in the trigeminal ganglion.

Exposed human pulp caused by trauma and/or caries in primary dentition: a histological evaluation

The aim of this study was to compare the pulpal reactions after exposure due to trauma and/or caries and to suggest the appropriate treatment options for the management of pulp, in the light of the histological findings in the primary teeth. Fifteen primary maxillary incisors with pulpal exposure were examined with light microscope in a blind study. After the histological evaluation, teeth were divided into three groups for the etiological factors due to the exposure according to the patient's files: trauma group, caries group and caries and trauma group. The inflammatory infiltration was diminished from the pulp chamber towards the apical third of the root canal in all of the examined teeth. Teeth in the trauma group presented fewer inflammatory cells in the root canal in comparison with other groups. It was concluded that the teeth with traumatic pulp exposure were considered as more likely to respond positively to pulpotomy technique. Pulpectomy or extraction seemed to be indicated for the decayed or decayed and traumatically injured teeth.

Immunoelectron Microscopic Analysis of CD11c-Positive Dendritic Cells in the Periapical Region of the Periodontal Ligament of Rat Molars

To increase understanding of structural and phenotypic characteristics of dendritic cells (DCs) in the periapical region of the periodontal ligament (PDL) of rat molars, we performed immunoelectron microscopy for CD11c, a previously untested DC marker. Results demonstrated that CD11c clearly recognized DCs, although it also labeled certain macrophage subpopulation(s). In the normal PDL, resident DCs that extended several long cytoplasmic processes from their oval to slender cell body were identified. When the PDL was bacterially challenged by three days of unsealed pulp exposure, relatively small, irregularly shaped DCs with many thin and short cytoplasmic processes, most likely representing newly recruited DCs, were detected. The ratio of DCs in CD11c+ cells was significantly higher than that in ED1 (anti-macrophages and DCs)-positive and OX6 (anti-major histocompatibility complex class II molecules)-positive cells in normal and challenged PDL.

Analysis of the contribution of nonresident progenitor cells and hematopoietic cells to reparative dentinogenesis using parabiosis model in mice

INTRODUCTION

The aim of this study was to analyze the contribution of nonresident progenitor/stem cells and hematopoietic cells to reparative dentinogenesis.

METHODS

Parabiosis was established between C57BL/6-TgN(ACTbEGFP)10sb/J transgenic mice (GFP+) and C57BL/6 wild-type mice (GFP-) to ensure blood cross-circulation between animals. Reparative dentinogenesis was stimulated by pulp exposures and capping on the first maxillary molar in the GFP- mice. Histologic sections of injured molars from GFP- mice were analyzed by epifluorescence microscopy to examine the contributions of GFP+ cells (nonresident progenitor cells and hematopoietic cells originating from GFP+ mice) to reparative dentinogenesis.

RESULTS

GFP+ cells were detected in close association with reparative dentin formed at the site of pulp exposure in the maxillary first molars of the GFP- mice.

CONCLUSIONS

The present study suggests the participation of the nonresident progenitor cells and hematopoietic cells in reparative dentinogenesis.

Consequences of crown fractures with pulpal exposure: histopathological evaluation in dogs

When a crown fracture involving pulpal exposure is produced, the therapeutic treatment to be applied depends to a great extent on the general histopathological condition of the exposed pulp. Hence, the objective of this study was to evaluate histopathological and bacteriological changes occurring in dental tissue and periradicular tissue of crown-fractured teeth with pulpal exposure. Twenty-four anterior teeth (central and lateral incisors) from the maxillary teeth of four young, adult Mongrel dogs were used. At 48 and 72 h after performing the crown fractures, the animals were sacrificed and the results evaluated. Both observation periods revealed the existence of an area of superficial inflammation with the formation of hyperplastic tissue towards the external surface. Intense neutrophilic infiltrate was observed below it. Mean depth of inflammation was greater at 48 h (4633.33 microm) than at 72 h (3933.33 microm), perhaps coinciding with the bigger pulp chamber opening (x1332.14 microm at 48 h vs. x479.52 microm at 72 h). Upon approaching the cervical portion, the inflammation became less. Bacterial contamination was constant in all the cases evaluated, worsening the histopathological findings with exposure time. This study demonstrates that when a crown fracture with pulpal exposure is produced, the success in treating it depends partly on how quickly therapeutic treatment is administered.

Dental pulp exposure, periapical inflammation and suppurative osteomyelitis of the jaws in juvenile Baltic grey seals (Halichoerus grypus grypus) from the late 19th century

The systematic analysis of museum collections can provide important insights into the dental and skeletal pathology of wild mammals. Here we present a previously unreported type of dental defect and related skull pathology in five juvenile Baltic grey seals that had been collected in the course of a seal culling program along the Danish coast in 1889 and 1890. All five skulls exhibited openings into the pulp cavities at the crown tips of all (four animals) or two (one animal) canines as well as several incisors and (in one animal) also some anterior premolars. The affected teeth showed wide pulp cavities and thin dentin. Pulp exposure had caused infection, inflammation, and finally necrosis of the pulp. As was evidenced by the extensive radiolucency around the roots of the affected teeth, the inflammation had extended from the pulp into the periapical space, leading to apical periodontitis with extensive bone resorption. Further spreading of the inflammation into the surrounding bone regions had then caused suppurative osteomyelitis of the jaws. The postcanine teeth of the pathological individuals typically had dentin of normal thickness and, except for one specimen, did not exhibit pulp exposure. The condition may have been caused by a late onset of secondary and tertiary dentin formation that led to pulp exposure in anterior teeth exposed to intense wear. Future investigations could address a possible genetic causation of the condition in the studied grey seals.

Pulpal response to different pulp capping methods after pulp exposure by air abrasion

Air abrasion is regaining popularity especially in the area of pediatric dentistry due to its ease of use and its advantages. Due to the lost of tactile information, while using this technique, there is an increased risk for pulpal exposure. On the other hand, Ca(OH)2 medicament has been proven to induce dentin bridge formation, but an adequate sealing seems to be even more important that the capping material used. The purpose of this study was two fold: to assess the pulpal response after pulpal exposure by air abrasion and to evaluate the healing potential after using Ca(OH)2 medicament or Liner Bond II as a capping agent. Two hundred sixteen teeth from mixed-bred dogs were used in this study. The teeth were divided into three groups, A) pulpal exposure by air-abrasion followed by sealing of the cavity with Liner Bond II, B) pulpal exposure by air-abrasion and Ca(OH)2 pulp capping and C) pulpal exposure by high-speed followed by air-abrasion and Ca(OH)2 pulp capping as a control group. The animals were sacrificed after 7, 14, 30 and 60 days and a histopathological evaluation was undertaken. After applying Analysis of Variance to compare the groups, it was observed that at earlier observation periods, the inflammatory criteria near the exposure site were different among the groups. As time elapsed, the inflammation was resolved in the pulp tissue, however, the odontoblastic layer and the dentin bridge formation had a highly statistically significant difference (p<0.001) among the various groups at all observation periods. In addition, a positive correlation was observed between the organization of the odontoblastic layer and the dentin bridge formation mainly after 30 days. It could be concluded that dentin bridge formation could be achieved with the use of Ca(OH) or Liner Bond II as capping agent with an adequate sealing. However, the formation is delayed especially when Liner Bond II is used as capping agent.

[An index for untreated severe caries]

Hardly any data are available on the clinical consequences of untreated severe caries, because there is no method to quantify the prevalence of oral conditions resulting from untreated caries. In the Philippines, an index was developed which records for (the location of) each tooth whether caries has reached the dental pulp, whether ulceration is present in the surrounding soft tissues due to sharp edges of fragments of a tooth lost due to caries, or whether a fistula or abscess is present. By adding the index to the existing Decayed Missing Filled Tooth index, insight is provided on the extent and the consequences of untreated caries and research may be carried out on its possible impact on the general health and wellbeing of national populations.

The influence of different therapeutic modalities and platelet rich plasma on apexogenesis: a preliminary study in monkeys

BACKGROUND

Traumatic injuries of permanent teeth with incomplete root formation are frequent during childhood. Adequate therapy is important for the further destiny of teeth with damaged pulp.

OBJECTIVES

To evaluate the effect of pulpotomy and high pulpotomy on the pulp and on root development, and the effect of platelet rich plasma (PRP) with hydroxyapatite (HAP) as a carrier and hydroxyapatite alone on apexogenesis.

MATERIAL AND METHODS

The study included eight monkeys (Cercopithecus aethiops) in which high pulpotomies were performed on the mandibular lateral incisors and canines, and pulpotomies were performed on the mandibular central incisors and premolars. The materials used in the study were commercial HAP (Apatec®, Stomygen) and PRP (prepared at the Torlak Institute of Immunology and Virology, Belgrade, Serbia.). Histological and radiological evaluations were done six months after the treatment.

RESULTS

Considering the differences between HAP+PRP treated teeth in the pulpotomy group and teeth in the high pulpotomy group, two times more root growth retardation was observed in the high pulpotomy group. In the high pulpotomy group, root growth retardation was less common in HAP+PRP treated teeth (42.9%) than in HAP treated teeth (50%). In the pulpotomy group, retardation of root development was also less common in HAP+PRP treated teeth (25%) compared to HAP treated teeth (50%). There were differences between the pulpotomy and high pulpotomy groups, but without statistical significance.

CONCLUSIONS

The application of endogenous growth factors in conjunction with the preservation of dental pulp vitality can result in a good outcome for pulp therapy of injured teeth, which means successfully completed apexogenesis.

Evaluation of clinical and microbiological features of deep carious lesions in primary molars

PURPOSE

Concern about the survival of microorganisms in deep carious lesions may often lead to unnecessary exposure of the pulp during excavation. This study evaluated the relationship between microbiological and clinical results of deep carious lesions in primary molars.

METHODS

Clinical evaluation was performed on 72 deep carious lesions considered to have pulp perforation after traditional excavation. The dentin color and consistency were assessed by means of standardized scales using the technique of Bjorndal et al before restoration. For microbiological examination, dentin samples were taken by a sterile bur and transferred to transport fluid, then plated on tryptic soy agar for growth of total colony forming units. Samples werethen transferred on Rogosa SL agar for growth of oral lactobacilli and on mitis salivarius agar for growth of mutans streptococci.

RESULTS

The proportion of mutans streptococci, lactobacilli, and total colony forming units increased when the dentin color and consistency increased. However, the proportion of lactobacilli was smaller than that of mutans streptococci in carious dentin samples.

CONCLUSIONS

Contrary to expectations, the findings showed that the number of bacteria in carious dentin of primary molars was not significantly excessive.

[Treatment strategies for deep caries]

Deep caries occurs when caries progresses to the deep dentin layer, and further progression has the risk of pulp exposure, which may affect pulp vitality and tooth longevity. Currently, there are no objective standards for the diagnosis of deep caries. In addition, traditional therapy for deep caries emphasizes complete debridement of the decayed tissue, resulting in an incremental high risk of pulp exposure. There are different views on how to deal with the remaining dentin after caries removal, and root canal treatment is often adopted directly after pulp exposure. In recent years, due to advances in dental pulp biology, bioactive pulp-capping materials, and clinical evidence-based medicine, the principle of deep caries treatment has shifted to pulp protection. Based on the latest international research progress, evidence-based medicine and expert consensus, we present a series of advancements in this article, including the terminology of deep caries, pathological changes and defense mechanisms of the pulp close to the deep caries, treatment principles of deep caries, technical strategies for carious tissues removal, and the decision-making of treatment protocols after pulp exposure, with the aim of enhancing the understanding of deep caries among dentists, as well as providing a reference for the clinical diagnosis and treatment of deep caries.

Vital Pulp Therapy of Young First Permanent Molars: A Retrospective Study on Radiographic Findings 24 Months Post-treatment

PURPOSE

With success rates comparable to that of root canal treatment, vital pulp therapy (VPT) has gained clinical interest and has been used in the management of young permanent teeth with inflamed pulps. The aim of the present study was to retrospectively evaluate the radiographic success of VPT in young first permanent molars 24 months post-treatment and correlate findings with tooth and treatment-related characteristics.

MATERIALS AND METHODS

Dental records of all patients with first permanent molars which received VPT in the Department of Paediatric Dentistry (National and Kapodistrian University of Athens) were retrieved. Demographic characteristics and data regarding the treatment performed were recorded. Patients' radiographs were evaluated at 6, 12 and 24 months post-treatment by two qualified paediatric dentists blinded regarding the treatment performed. Radiographic success, reasons for failure and continuation of root development were evaluated. Differences were tested using the Χ2 and Student's t-test, and possible correlations were determined by calculating the odds ratio.

RESULTS

Overall radiographic success rate at 24 months was 77%, ranging between 50% for direct pulp capping and 92% for full pulpotomy. Differences were not statistically significant. Continuation of root development was recorded in almost 1/3 of the teeth and completion in almost 1/5. No statistically significant association was recorded between the outcome and any tooth and treatment-related variables.

CONCLUSION

VPT seems to be a reliable option in the long term for the treatment of deep carious lesions in young permanent molars.

Equivalency study of histological responses to complete or partial pulpotomies in inflamed baboon immature first permanent molars

Partial pulpotomy is an accepted treatment for traumatised incisor teeth with exposed pulps. Clinical studies in humans suggest that this may also be an acceptable technique for carious exposed pulps in molar teeth, but objective histological evidence to support this perception is lacking.

OBJECTIVE

To compare histological responses to complete or partial pulpotomies of inflamed pulps in immature baboon first permanent molar teeth.

METHODS

An experimental study in the baboon (Papio ursinus). Pulpitis was induced with fresh Streptococcus mutans placed into occlusal cavities with a small pulpal exposure in 34 first permanent molars of 9 juvenile baboons. After 14 days a pulpotomy, either complete or partial, was performed on the same molars in contra-lateral quadrants using calcium hydroxide covered with IRM and amalgam. After 90 days specimens were harvested and examined under the light microscope with the examiner blind to the treatment.

RESULTS

Reaction frequencies in the complete and partial pulpotomy teeth were: dentine bridges 9/16 and 10/16, viable pulp in root canals 10/16 and 13/18, peri-apical abscesses 3/13 and 4/13. Fisher's exact probability test showed no statistically significant rates between the groups.

CONCLUSIONS

Complete or partial pulpotomy of inflamed pulps in immature baboon first permanent molars produced comparable reactions.