Dental Science for Dental Assisting Exam Study Guide (page 3)

Updated on Jun 23, 2011

Blood and Nerve Supply

Arteries and veins carry blood to the neck and face. The internal carotid artery carries blood to the brain, and the exterior carotid artery carries blood to the face and mouth. There are 12 pairs of cranial nerves.


Sinuses are air-filled cavities in the face and skull that produce mucus. There are several sinus cavities: ethmoid sinuses, sphenoid sinuses, maxillary sinuses, and frontal sinuses. The sinuses can become blocked, which can cause discomfort for the patient similar to a toothache.

Dental Caries Process

Dental caries are known as tooth decay and are often called “cavities” by patients. This is an infectious process. Caries is caused by a bacterial infection and is contagious. The bacteria are found in dental plaque. The bacteria can be transmitted from person to person. The condition of the mouth must have the following present for caries to form: Lactobacillus (LB) bacteria, Mutanstreptococci (MS) bacteria, a diet high in fermentable carbohydrates (sugars), and a susceptible tooth.

Caries Process

The caries process takes approximately two years, but it can be halted or disrupted.

Stages of Carious Lesions

  • Incipient: This is the very start of tooth decay. The decay has not yet reached the dentinal layer.
  • Overt: The decay has reached the dentinal layer, and there is a visible hole in the tooth.
  • Rampant: There are overt carious lesions present in many teeth in the mouth at the same time. This is common in patients with poor oral hygiene.

Diagnosis of Caries

A dentist will check for dental caries at each exam appointment. There are two main ways in which a dentist can detect caries: radiographs and dental explorers.


Radiographs, or X-rays, are one of the best tools a dentist has to detect caries interproximally. Today, many dentists use digital radiographs that eliminate the need for film.

Dental Explorers

The explorer is used to check the surfaces of the teeth. The explorer will stick to any suspicious area.

Periodontal Disease Process

Today, 75% of Americans have some form of periodontal disease.

Causes of the disease

The causes of periodontal disease are dental plaque and calculus. Bacteria in dental plaque cause inflammation and destroy tissue. The tissues will pull away from the plaque and bacteria, creating a periodontal pocket. More plaque and bacteria fills the periodontal pocket and hardens. Calculus is hardened plaque, and it is also called tartar. It builds up on the surface of the teeth, irritating the surrounding tissues and perpetuating the disease cycle.

Types of Periodontal Disease

Type I: Gingivitis Gingivitis is the inflammation of the gingiva, which can be caused by lack of oral hygiene, hormonal imbalance, or illness. It is totally reversible at this stage.

Type II: Early Periodontitis There has been a progression from gingivitis into the non-reversible start of periodontal disease. Early periodontitis is the beginning of the periodontal disease process. At this stage, the patient will experience bleeding and maybe some generalized or localized swelling of the gingiva. Pockets may have increased in size.

Type III: Moderate Periodontitis This is the middle stage of the disease process. There has been further progression of the disease. At this point, surgery may be recommended by the dentist or specialist. Bleeding has increased, pockets have grown in size, and the patient may be experiencing bad breath and/or swelling.

Type IV: Advanced Periodontitis The supporting structures of the mouth are being destroyed by the disease. There has been more damage and destruction to the periodontium. The patient is experiencing pain, increased bleeding, tooth mobility, swelling, and extreme bad breath. The patient will lose his or her teeth.

Signs and Symptoms

There are several signs and symptoms of periodontal disease. These include loose teeth, pain when chewing, gums that bleed easily when brushing or flossing, redness, swollen gingiva, bad breath, soreness, and tenderness. In the early stages, periodontal disease is often painless and has minimal symptoms. Early detection through regular examinations is crucial.

Effects on Systemic Health

Periodontal disease has an effect on the entire human body. Whenever there is disease present in the human body, the immune system reacts. Periodontal disease causes the immune system to be on constant alert, thereby making the patient more susceptible to other illnesses by weakening the immune system. Periodontal disease has been scientifically linked with premature childbirth, heart disease and stroke, bacterial pneumonia, and diabetes.

Preventive Dentistry

The goal of dentistry is for the patient to keep his or her own teeth for life. This can be achieved through education by working together with the patient as a team regarding a preventative routine.

Patient Maintenance

Patients will be educated regarding the importance of cleanings and examinations every six months, sealants, and oral hygiene at home. The patient will establish an oral hygiene routine and schedule for maintaining dental health with help from the dental team.

Routine Cleanings

A dental prophylaxis should be performed every six months to maintain a proper cleaning schedule. This procedure may be performed by a dentist or dental hygienist.

Fluoride Treatments

Fluoride is a naturally occurring mineral found in many of the items that we use daily. Some community drinking water is fluoridated. Many types of toothpaste contain fluoride. Fluoride treatments are applied topically and allowed to contact tooth surfaces for a designated amount of time in the dental setting. Fluoride drops and supplements are prescribed by physicians and dentists to prevent tooth decay in babies and young children.


This preventive measure is a form of flowable composite that is placed into the pits and fissures on the occlusal surfaces of posterior teeth. This technique has been proven to prevent decay on the occlusal surfaces (not interproximal) and is recommended as soon as the permanent teeth have erupted fully into the oral cavity.

Oral Healthcare Instructions

The dentist depends on the dental assistant to provide the patients with accurate, concise oral hygiene instructions. In some offices, the dentist may ask the assistant to present treatment plans as well. Dental assistants are often the dental healthcare provider the patient will look to for clarification of the treatment being recommended by the dentist. It is important for dental assistants to understand the procedures they are assisting in and how to explain each step to the patient in a calm, reassuring, and informative manner.


A patient’s diet can have an impact on his or her dental health. Dental assistants are often tasked with discussing proper nutrition with the patient and/or the patient’s family. There are many different ways to discuss the importance of nutrition in a dental setting.

Food Pyramid

The food pyramid was designed and is maintained by the Food and Drug Administration (FDA). The pyramid’s aim is to help Americans know how many servings from each food group should be consumed for optimal health and nutrition. When discussing nutrition, it is important to refer to this guide.

Vitamins and Minerals

Vitamins are essential to good oral health as well as overall health. The best way to receive these vitamins is from nutritious food, but supplements can help as well. Minerals are essential for optimal health. Both vitamins and minerals occur naturally in the food and drink we consume. This is why it is important to have a good balance between fruits, vegetables, grains, dairy, oils, meats, and legumes.

Carbohydrates, Proteins, and Fats

Carbohydrates are products in foods that the body converts into energy. Proteins are essential to build and repair tissues. Fats protect the organs of the body and are utilized as sources of energy.


Water is often referred to as “the forgotten nutrient.” Humans cannot survive without water. Humans can go longer without food than without water. The oral cavity needs water to remain hydrated. The FDA recommends that adults have eight glasses of water per day. Water is also found in some foods we eat.

Eating Disorders

Eating disorders can affect both men and women of all ages, and are usually associated with self-image issues. The two leading eating disorders are anorexia nervosa and bulimia nervosa. In the oral cavity, dental healthcare providers can see the effects of these two disorders. The enamel layer is actually eaten away by the acids from the stomach each time patients cause themselves to vomit. The damage is quite obvious upon examination. The dental team is obligated to offer help to patients by referring them to a mental health professional.

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