RELATIONSHIP BETWEEN DENTAL HISTOLOGY AND DENTAL EMBRYOLOGY

Introduction

 Oral histology and embryology touches on the development and growth of teeth and oral cavities, as well as the structure and development of salivary glands and more. Though it’s a complex subject that encompasses many facets, it’s material you’ll have to become familiar with if you’re interested in pursuing dental hygienist training or becoming an intra-oral dental assistant, as it will help you understand normal facial development and will prepare you to care for patients with abnormalities or dental pathologies.

So what do we really mean when we use terms like “histology” and “embryology”? Let’s try to break it down into material that’s a little simpler to understand.

Relationship between dental histology and dental embryology

The basics

 Histology is the science and study of tissues. Histo means “tissue,” while Logy means “the science of.” By studying oral histology and embryology, you’ll gain a strong foundation in oral biology. The material you’ll study will focus on the development and structure of cells and tissues, the stages of tooth development and maturation, the different components of a tissue, like cells, intercellular substance and tissue fluids, and the different components of a human tooth, like enamel, dentin, dental pulp and cementum. To understand how the mouth functions, it’s critical that we know how cells become tissues. Why is it so important? Well, by better understanding how teeth evolve over time, we can develop superior techniques to prevent caries and other dental problems in advance. For example, did you know that the correct method of brushing teeth that professionals with dental assistant training recommend today is based on our knowledge of oral histology?

Enamel 

 The hardest tissue in the human body, enamel is made mostly from calcium phosphate in the form of hydroxyapatite crystals. Because of this, enamel can’t regenerate, which means it will slowly experience wear and tear over time. An absence of enamel can lead to a number of problems for teeth, such as greater vulnerability to caries.

Dentin

The bulk of the root of a tooth, dentin is made of dentinal tubules. In the inner dentin, there are nerves present, which is why when the enamel of a tooth is gone, a person can experience pain or sensitivity. Dentin also works hand in hand with pulp, as dentin grounds pulp while pulp nourishes dentin.

Pulp

 Pulp is the only soft tissue of the tooth. It’s also a loose connective tissue kept in place by dentin. Pulp is very sensitive, so it will respond to any sensation of pain, and it also connects to the lateral canals of the root. Lastly, the average volume of the pulp is about 0.03 cm3, so it’s quite small.

Cementum

 Cementum is comparable to bone. Its function is to hold the tooth in place to keep it in a functional position. Like dentin, cementum will form throughout life, so it’s in no danger of running out. There’s much less cementum near the enamel, which is why the tooth can be in trouble when the enamel runs out.

The inception of the profession of dental hygiene was supported by research conducted nearly 100 years ago. Dr. Alfred C. Fones opened the first school of dental hygiene, developing the concept of prevention specialists called “dental hygienists.” Previous attempts to establish formal courses for “dental nurses” had failed, and Fones preferred the term dental hygienist rather than dental nurse because of his commitment to providing preventive interventions and teaching children oral hygiene for prevention of dental diseases. In 1914, one year after the origin of dental hygiene in 1913, Fones launched a project to collect data to document the effectiveness of these dental hygienists in the schools providing assessments and oral prophylaxes and teaching students about oral hygiene at home as disease prevention measures. The theory was that early education regarding oral hygiene could impact oral health throughout the lifespan. The Fones' Five-Year Demonstration Project, initiated in public schools, provided documentation of the success of dental hygienists in education and dental disease prevention. Fones' conceptualization of the dental hygienist as an oral disease prevention specialist provided the initial focus and framework for the discipline and its specialized body of knowledge.

Over 20 years later, Brooker presented a seminal paper to the New York State Dental Hygienists' Association titled, Oral Hygiene as an Exact Science. This article was published in the Journal of the American Dental Hygienists' Association (JADHA, now JDH) in 1926.7 He presented information grounded in a decade of research that documented the effectiveness of “mouth cleanliness” in the prevention of dental diseases. The question of the health and preventive value of oral hygiene was raised when Brooker asked the audience, “Does hygienic care of the surfaces of the teeth and gums prevent disease, or are you merely cosmeticians and beauticians…” He emphasized how critical it is to have the public's confidence in the effectiveness of dental hygiene care for disease prevention if the dental hygienist was to proceed constructively. Brooker went on to assert that a careful review of the available data at that time demonstrated that the principles underlying dental hygiene services were “as exact in their scientific details as those upon which dentistry is practiced.” This tenet suggested the importance of dental hygiene research to the profession, dental hygiene practice and the public. However, research did not become a responsibility of dental hygienists until much later. It is interesting to note that many of today's preventive oral health principles and practices were first described a very long time ago indeed.

Conclusion

 In 1940, American Dental Hygienists' Association (ADHA) President Perry emphasized in her address before the same annual meeting in New York 14 years later that it was important to promote an understanding of scientific procedure. However, she went on to say that producing dental hygienists who are scientists was “improbable.” Part of the reason for this opinion, of course, was related to the short term of education prescribed for dental hygienists.

Some of the earliest dental hygiene research manuscripts published in JADHA in 1945 and 1946 reported results of dental hygiene education studies, although research manuscripts comprised far less than 10% of the Journal.The first research article was entitled, Report on the Curricula on Training for Dental Hygienists, by Greenwood, a dentist and chair of a dental hygiene program. Early dental hygiene programs were 8 months to 1 year in length, and the first uniform minimum requirement for programs to be 2 years in length was not established until 1947. The results of this early dental hygiene education research is credited, at least in part, with the establishment of minimum educational standards of 2 years. Advanced education at the graduate level, however, is a requirement for scholarly activity and research in a discipline.

References

·         Policy Manual [Glossary, 4S-94/19-84]. American Dental Hygienists' Association [Internet]. [cited 2013 March 24]. Available from: http://www.adha.org/downloads/ADHA_Policies.pdf Google ScholarOxford Dictionary.

·        Oxford University Press [Internet]. 2013 [cited 2013 March 24]. Available from:http://oxforddictionaries.com/us/definition/american_english/discipline

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