Naotake Akimoto

The Caries Phenomenon: A Timeline from Witchcraft and Superstition to Opinions of the 1500s to Today's Science

This historical treatise follows the documented timeline of tooth decay into todays understanding, treatment, and teaching of caries biology. Caries has been attributed to many different causes for several millennia, however, only since the late 1900s has research revealed its complex multifactorial nature. European writers of the 1600s to 1700s held views that general health, mechanical injuries, trauma, and sudden temperature changes all caused caries—holding a common belief that decay was due to chemical agents, faulty saliva, and food particles. Until the early 1800s most writers believed that caries was due to inflammation from surrounding diseased alveolar bone. Todays science has demonstrated that caries is caused by indigenous oral microorganisms becoming a dynamic biofilm, that in the presence of fermentable sugars produce organic acids capable of dissolving inorganic enamel and dentin followed by the proteolytic destruction of collagen leaving soft infected dentin. As bacteria enter the pulp, infection follows.

How histology enriched endodontics as a specialty & nurtured pulp biology: Our endodontic continuum from 1528 into the 1900’s – Part I

The 1980 Oral Science Monograph by L.J. Baume of Geneva is an erudite review, which recognized notables who elevated the respect of histology of dentine & pulp to scientific maturity [1]. Before 1500, “dental surgery” was basically tooth extraction until 1528 when Johannes Stocker recommended treating tooth pain with pulp cautery & filling some canals with copper. Microscopic observation began in 1675 when Anton van Leeuwenhoek (1632-1723) described transparent pipes from pieces of his wife’s tooth using his homemade microscope & compared tooth enamel & cementum to tree bark. In 1824, Edward Hudson (1762-1857) of Philadelphia cauterized the tooth pulp & plugged the canal with gold foil. In 1840, Robert Owen (1804-1892) received recognition by many colleagues for introducing the histologic term DENTINE into our dental lexicon. Histologic knowledge of normal & pathologic tooth tissues rapidly advanced with microscopic technologies of sectioning & staining. In 1879, professor Adolph Witzel’s (1847-1906) histological study described pulp inflammation & neo-dentine formations following vital pulp capping of human teeth treated with arsenious acid—he is recognized as the father of histological endodontics [2]. Grossman’s 1940 textbook advanced ENDODONTICS as a US clinical specialty by promoting DIFFERENTIAL DIAGNOSIS in patients who were suffering from pulpal or periapical pathology, which led to PROGNOSIS & TREATMENT based on a blend of clinical observations with knowledge of pulp histology. Histological advancements of tooth tissue rapidly advanced the knowledge of normal & pathological healing, which fostered ENDODONTICS & RESTORATIVE clinical specialties in the early 1900’s. Dr. Wm. Cotton personally backed the PULP BIOLOGY GROUP as a research specialty during the 1975 London IADR meeting. Endodontic tooth treatment rapidly progressed by using new technologies to assist the diagnosis & treatment of tooth infections. Correspondence to: Charles F. Cox, DMD, PhD, Department of Operative Dentistry, School of Dental Medicine, Tsurumi University, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan, Tel: (810)-275-8361; Fax: (810)636-4201, E-mail: cfcox@phoenixdental.com

A Timeline of Biological Assessments: Our Nonspatial Continuum

Much of our dental history is recognized through oral tradition, which has led to myths and misconceptions regarding the efficacy of early restorative agents. Dental biomaterial history has tended to report only certain aspects research in a few textbooks that are expensive and not readily available to the larger dental audience. Our purpose is to provide a detailed peer-reviewed document, which provides a chronological account of our in vitro and in vitro biological continuum. This document follows a published historical chronological timeline of biomaterial testing literature beginning with its little known inception in 1779. Many of the early dental restorative agents evolved due to their anodyne capacity to alleviate tooth pain and provide a modest bacteriostatic capacity. Those that were successful were modified as temporary cavity filling agents and evolved to more permanent fillings. Unfortunately, many of the early agents e.g. antimony, arsenic, asbestos, canthrides, formalin, mercury, mustard, phenol to name a few were toxic to the tooth and supporting periodontal tissues as well as failing to support lost tooth structure. The National Institute of Dental Research required biomaterial testing in the late 1940’s. Even today, the agency permits many pre-1950 agents via the grandfather clause for commercial inclusion and clinical use, while requiring all new post-1958 agents to pass both in-vitro and in vivo testing hurdles. We routinely place restorative agents that infiltrate in graded interphases to interdiffuse into vital enamel, dentine and even cementum by forming a unique biomimetic substrate that mimics the color and opacity of the human tooth. Our biological continuum is still evolving with technologies that will continue to change our clinical future. Our profession has been the global benefactor of dynamic change. Unfortunately, our biomaterials testing status quo is not acceptable as many toxic agents e.g. formalin still remain in our clinics.

A timeline of biological assessments: Our nonspatial continuum

Much of our dental history is recognized through oral tradition, which has led to myths and misconceptions regarding the efficacy of early restorative agents. Dental biomaterial history has tended to report only certain aspects research in a few textbooks that are expensive and not readily available to the larger dental audience. Our purpose is to provide a detailed peer-reviewed document, which provides a chronological account of our in vitro and in vitro biological continuum. This document follows a published historical chronological timeline of biomaterial testing literature beginning with its little known inception in 1779. Many of the early dental restorative agents evolved due to their anodyne capacity to alleviate tooth pain and provide a modest bacteriostatic capacity. Those that were successful were modified as temporary cavity filling agents and evolved to more permanent fillings. Unfortunately, many of the early agents e.g. antimony, arsenic, asbestos, canthrides, formalin, mercury, mustard, phenol to name a few were toxic to the tooth and supporting periodontal tissues as well as failing to support lost tooth structure. The National Institute of Dental Research required biomaterial testing in the late 1940’s. Even today, the agency permits many pre-1950 agents via the grandfather clause for commercial inclusion and clinical use, while requiring all new post-1958 agents to pass both in-vitro and in vivo testing hurdles. We routinely place restorative agents that infiltrate in graded interphases to interdiffuse into vital enamel, dentine and even cementum by forming a unique biomimetic substrate that mimics the color and opacity of the human tooth. Our biological continuum is still evolving with technologies that will continue to change our clinical future. Our profession has been the global benefactor of dynamic change. Unfortunately, our biomaterials testing status quo is not acceptable as many toxic agents e.g. formalin still remain in our clinics.

Operative dentistry’s beginnings & its rapid but steady continuum

Generations before sugar was implicated with caries—vitamin-C deficiency (scurvy) had plagued humans for millennia. Early humans treated tooth pain with folkremedies & bloodletting by moonlight—when these cures failed, roadside itinerants with little training promoted extractions. King Philip II established the Parisian Barber-Surgeon Guild in 1210, requiring proper credentials to extract teeth. Edentulous US colonists of the 1800’s supported development of MECHANICAL DENTISTRY to fabricate dentures with artificial teeth. Cheap sugar inspired increased consumption, creating a rapid increase in worldwide caries. OPERATIVE DENTISTRY advanced in the Americas with a few clinicians attempting removal of cavity debris, decay, cleansing & restoration with agents to reestablish form & function. Dr. C.A. Harris of Ohio is acknowledged to have actively endorsed dentistry as a clinical profession. Dr. M.H. Webb’s 1883 OPERATIVE DENTISTRY textbook commanded international recognition by defining gold-foil cavity preparation & restoration, stressing attention to detail. By 1890, Dr. G.V. Black had outlined scientific guidelines for amalgam composition & defined OPERATIVE cavity resistance & retention form & restoration. By 1839, Drs. Harris & Hayden were recognized to have given OPERATIVE DENTISTRY its parturition at Baltimore Dental College. By 1870, America gained international respect with the founding of 9-accreditated dental schools. US clinicians organized active regional dental societies, developed vulcanite-dentures, scalers, rubber-dam, adjustable dental-chairs, steel burs, electric-handpieces, round-end burs, mouth-mirrors, matrix bands, local anesthesia & more. Circa 1967, Professor Takao Fusayama of Tokyo Medical Dental College introduced a caries stain that was 1st to differentiate non-vital from vital dentine & defined MINIMAL CAVITY INTERVENTION & restoration with polymers that hybridized vital enamel & dentine. This OPERATIVE continuum has endeavored to examine those dental materials & technologies, which have advanced our OPERATIVE standards. “Pay attention to the details—never be content with what you know—there is always more” Dr. Miles Markley (1903-2000). Correspondence to: Dr. Charles F. Cox, DMD, PhD, Department of Operative Dentistry, School of Dental Medicine, Tsurumi University, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan, Tel: 1 (810) 275-8361; Fax: 1 (810) 6364201, E-mail: cfcoxctwos@gmail.com