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Objective: The number of older patients requiring restorative treatment are likely to increase due to improvements in oral health and increased longevity. However, aging odontometric data are lacking. The aim of this study was to determine possible changes in pulp cell density, pulp area, and dentinal thickness with age., Study Design: Incisors (50), canines (39), premolars (51), and molars (7) extracted from 60 patients aged between 10 and 59 years, were analyzed histomorphometrically for cell density (odontoblasts, subodontoblasts, and pulp core fibroblasts) and dentinal thickness., Results: With increasing patient age, in both crown and root aspects of teeth, dentinal thickness increased (P <.001), while the density of odontoblasts (P <.001), subodontoblasts (P = 0.001), and pulp fibroblasts (crown, P <.011; root, P =.0015) decreased. The degree of age-related changes in teeth appeared to be asymmetrical, with decreases in the root being greater than in the crown. At all ages pulp cell densities, including odontoblasts, within the crown were greater than in the root (P <.001), even though the calculated rate of dentinal deposition was greatest in the root., Conclusion: Decreases in pulp cell density may reduce pulp repair activity after restorative treatments, although increases in dentinal thickness may aid pulp protection. An understanding of these age-related changes will influence the provision of restorative and endodontic care and benefit older patients.

In order to substantiate biocompatibility of dental materials and techniques and thereby reduce iatrogenesis, tests for pulpal and dentinal responses have been developed. These have shown that: high-speed tooth cutting techniques are superior to low-speed techniques even when both incorporate air and water coolant sprays; pressure when condensing restorative materials intensifies pulpal responses induced by the cutting procedure, and that chemically self-cured resin composites requiring the application of a matrix to enhance adaptation intensify pulpal response as compared to visible light-cured equivalents applied incrementally, fully cured throughout and not requiring the pressure of a matrix. Most cements are irritating to the pulp especially when used as luting agents and when used less than 0.5 mm from it. Conditioning agents utilising weak acids for short periods induce little irritation whilst bonding agents appear to be beneficial by providing protection from subsequently placed restorative materials. Clinicians should make every effort to minimise the development of pulpal responses and reduce iatrogenic effects.

Dental materials and devices are being treated more like drugs and now have to meet the safety and efficacy requirements of drugs and medical devices. Biocompatibility is the key word. The history of the development of controls, standards, and guidelines began almost 500 years ago and is detailed in a chronological fashion up to the present time. An outline of the latest revised draft of the international document (ISO Technical Report No. 7405), to be completed hopefully by 1993 in time for the harmonization of the European Standards within the EC, is presented. The types of tests (initial, secondary, and preclinical usage tests) are listed and described. No amount of experimental study can guarantee absolute safety for any substance. However, toxicological investigations provide data from which reasonable projections and predictions can be made about the conditions under which the product can be safely used. It is the intent that this Technical Report be reviewed regularly and revised, with the ultimate objective of converting it to an International Standard.

When glass ionomer cements were initially introduced, the pulpal responses were considered milder relative to other cements. However, the results mainly came from the application of glass ionomer cements as restorative materials. When ultimately tested with the basic laws of biocompatibility required of other cements, especially a luting agents, little difference has been shown. The judicious use of calcium hydroxide is highly recommended.

In reviewing 356 instances of pulp capping during the past 25 years, 149 cases were recalled with posttreatment intervals greater than five years. One hundred thirty teeth (87.3%) were still vital and functioning with an average posttreatment interval of 11.7 years. The criteria for pulp capping procedures are in need of revision. Restrictions based on tooth size and age of the patient are unfounded.

Calcium hydroxide, in its various forms, has become the preferred agent of most practitioners who perform pulp capping. The application of calcium hydroxide to the pulp stimulates the growth of new dentin and protects the pulp from subsequent irritation. However, the new dentin generated by the pulp may, in turn, infringe on the pulp. If the thickness of the pulp tissue is large, this infringement will not be significant. If the volume of pulp tissue is shallow, the same amount of infringement may cause sufficient impairment of circulation to the cornal area of the pulp, leading to an area of the necrosis may then contaminate the entire pulp, and root canal therapy will become necessary. Therefore, pulpal amputation is the preferred treatment in such situations.

Previous studies have shown that sequential application of an acidified solution of ferric oxalate, N-phenylglycine and PMDM (the reaction product of pyromellitic dianhydride and hydroxyethyl methacrylate) yields strong adhesive bonding of composite resins to both dentine and enamel. The purpose of this study was to evaluate the clinical characteristics and the biocompatibility of this system in human teeth scheduled for extraction in the course of orthodontic treatment. Controls were light-cured Scotch-bond or ZOE in contralateral teeth. Evaluation criteria, which included clinical feasibility, patient acceptability, retention, margin aesthetics and human pulp response, were met. Within the 4-241 day observation periods, there was no postoperative sensitivity, pain, loss of retention, staining or discolouration. All pulp responses (double-blind pulp analysis including all teeth) were acceptable. With mean (+/- SD) remaining dentine thickness (RDT) of 0.67 +/- 0.35 mm, all indicators of pulp inflammation (displacement, superficial response, deep response etc.) averaged between none and slight, under 1 on a 0-4 scale. Both controls gave similar results. Linear regression analysis indicated low responses at all RDTs. The experimental material is safe and effective; further unrestricted clinical evaluations in teeth to be retained are indicated.

The newer composites, although free of methacrylic acid and of a neutral pH, were still found to be toxic to the pulp. The intensity of response was increased after acid pretreatment procedures; this indicates an increase in dentin permeability. When the remaining dentin thickness was 1.0 mm or less, regardless of whether the dentin was primary dentin or primary and reparative dentin, the percentage of teeth with abscess formations increased. Use of calcium hydroxide bases or liners to coat the dentin before acid pretreatment of enamel is therefore highly recommended.

A case of a molar on which a vital hemisection was performed a year before extraction, and which remained clinically asymptomatic during that time, illustrates the regenerative powers of the pulp.