Dentistry is a medical science which deals with study of Morphology, Anatomy & Physiology of our precious TEETH and associated different diseases and their remedies by adopting different medicinal treatments and surgical procedures.
Any disorder of Oral cavity in the dentition itself and in Oral mucosa of adjacent structures and tissues, particularly in Jaw and Facial area are also part of dentistry.
The preventive dental care is very important to avoid any dental disease. The diagnosis, treatment or, cure, precautions and corrective care play an important role to maintain our teeth.
Formation, development & arrangement of teeth:
The formation of primary teeth in unborn baby initiates during 6-8 weeks of pre-natal development and then, permanent the growth of teeth begins in around 20th week. If teeth are not developed during this stage, the Hypodontia (a condition in which any teeth may be missing) may occur.
The primary teeth (milk teeth) are available even at the time of birth but, they not visible that time. The development of teeth starts from 6 months and they are fully developed after 1.5 years. The complete growth of Molars take even more time.
These teeth are slowly resorbed and then, permanent teeth are redeveloped from 4-5 years till 16 years. The redevelopment of molars take yet more time may be upto 18-25 years.
Human body has deciduous type of teeth where, initially, primary (temporary or, milk) teeth are formed and then, permanent teeth are redeveloped. An infant (Antenatal) have 20 teeth (without 3×4=12 Molars in each quadrant).
There are 32 teeth in an adult body out of which 16 teeth are arranged in upper jaw (Maxillary) and 16 in lower jaw (Mandibular) portion of mouth. Both upper and lower series of teeth are again divided in 2 parts viz: left and right side. This way, there are 4 quadrants and in each quadrant, 8 teeth are arranged in following manner:
· Incisors (Central & Lateral) – 2 nos.
· Canine (Cuspid) – 1 no.
· Pre-Molars – 2 nos.
· Molars – 3 nos.
Dr. Adolf Zsigmondy, a Hungarian dentist (lived in Vienna, US) was the first who had conceived the idea of charting teeth in a cross, called Zsigmondy cross (named after him) in June 1816. The same charting method is presently used all over the world. Dr. Adolf was 1st to describe the contact & wear of the approximal side of teeth. He had also developed procedure of cohesive Gold fillings.
A normal tooth is chiefly made up of 2 parts viz: Crown which is Visible and comprising of Enamel, Dentine & Pulp and Root which is not visible and comprised of Gums, Bone, Root canal, Cementum, Nerves & Blood vessels.
The upper and lower (maxillary and mandibular) incisors are most visible teeth as compared to any other tooth because they are centrally located in the front of mouth. The central incisors are rectangular or, square in shape. The main function of these teeth is to cut the food into small pieces and to prevent the food, coming out from mouth while, being chewed.
The canine teeth are pointed at tip, also called Cuspid and are called the “cornerstone” of mouth. They separate premolars from incisors. The main function of canine teeth is to tear the food. There is a single cusp on canines in each quadrant and they resemble the prehensile teeth, found in carnivorous animals.
The Premolars or, Bicuspid means 2 cusps are available in each Premolar and they are situated between Canine and Molars. The Premolars are no deciduous, hence, the teeth that precede the permanent premolars are the deciduous molars. The main functions of premolar teeth are to tear, chew and partially grind the food before it is engulfed.
These teeth are situated at most posterior side in the mouth in every quadrant. Their function is to tear & grind the food during chewing. The overall appearance may vary among the different molars, depending on the number of cusps in different people. The 3rd molar is also called “wisdom teeth.”
It is an important part of tooth, found in 2 forms viz: Clinical crown which is visible in the mouth and Anatomical crown which is not visible in mouth. This area is found above the Cementoenamel Junction (CEJ) or Neck of tooth. The crown is composed of dentin, with the pulp chamber within. The crown is enclosed within bone before the tooth erupts, but after eruption the crown is almost always visible in an anatomically normal and clinically healthy mouth.
The anatomic root is found below the CEJ which is covered with cementum, and the clinical root may be any part of a tooth but, it not visible in the mouth. Dentin, composed of root, has the pulp canals. The roots of teeth may be single in number (single-rooted teeth) or, multiple. The Canines and mostly all premolars (except for maxillary first premolars) have one root. Maxillary first premolars and mandibular molars normally have two roots. Maxillary molars have three roots. The tooth is supported by periodontium in bone.
The teeth are defined by their surfaces and each surface has its name as defined on the basis of its location inside the mouth, which may be closer to cheeks or to the tongue. The surface which is closer to cheeks is called Buccal, the surface closer to lips is called Labial and those closer to tongue are referred to as Lingual. The Lingual surfaces of teeth in the upper arch (maxillary teeth) are known as Palatal.
The upper part of teeth which come in contact during chewing are known as Occlusal on posterior or back region teeth and Incisal on anterior or front teeth. The Surfaces nearest to the junction of the crown and root are called Cervical, and those closest to the apex of the root are known as Apical.
The Mesial surface is towards the median line of the face and the surfaces away from the median line are known as Distal.
The cusp is an elevation on Occlusal surface of teeth. It contributes to a significant portion of the tooth’s surface. Canines have one cusp. The maxillary all premolars and 1st mandibular premolar have 2 cusps. But, the mandibular 2nd premolar has three cusps – 1 Buccal and 2 Lingual. Maxillary molars have 2 Buccal cusps and 2 Lingual cusps. Another 5th cusp, may be available on the maxillary 1st molar, is known as the Cusp of Carabelli. The mandibular molars may have 4 or, 5 cusps.
It is a convexity, resembling a girdle which is encircling the lingual surface at the cervical. All anterior teeth are formed from 4 centers of development, known as Lobes out of which, 3 are located on the facial side and 1 on lingual side of mouth.
A cingulum is poorly developed or, may be absent on lower incisors while, maxillary canines have a large & well developed cingulum. The cingulum of mandibular canines is smoother and rounded.
Any linear and flat elevations on teeth are called Ridges and named according to their location.
The teeth demonstrating the least number of developmental grooves are the mandibular central and lateral incisors. However, the canines show the most prominent developmental grooves, because they have robust bonding with the bone.
These Embrasures are triangular shaped spaces located between the proximal surfaces of adjacent teeth. The borders of embrasures are formed by the interdental papilla of the Gingival (Gums), the adjacent teeth and the contact point where two teeth meets.
The Embrasures have three functions. They form the spillways between teeth so as to direct the food away from the gingiva. They also provide a mechanism for self cleaning of teeth. Lastly, they protect the gingiva from frictional trauma but, provide the proper stimulation to the tissues.
The Mammelons are usually found as 3 small bumps on the incisal edges of anterior teeth. They are the remnants of three lobes of formation of these teeth, the 4th lobe represented by the Cingulum. Since this surface of the tooth wears away very fast, hence, the mammelons may not be visible on teeth of elderly persons. The presence of mammelons in adults is an indication of malocclusion.
Disorders and symptoms:
The common dental disorders are: Bad breath, Canker Sores, Gingivitis, Pyorrhea, Hypersensitivity of teeth, Toothache, Teeth whitening, tooth decay etc.
The symptoms of dental disorders include the formation of cavities (caused by tooth decay), pulpitis, peri apical abscess, infected teeth, malocclusion, fractured, loosened and knocked out teeth, Bruxism and Attrition.
The excessive wear of tooth surface may be caused by Bruxism (jaw’s clenching and grinding of the teeth).
The loss of tissues of tooth, due to excessive tooth-to-tooth contact, causes Attrition, usually starting at the incisal or occlusal surfaces.
If attrition is severe, the enamel can be completely worn away leaving underlying dentin exposed, resulting in an increased risk of dental caries & dentin hypersenstivity.
Dental treatment or, procedures:
· Teeth whitening: The teeth whitening is done by Bleaching. It reduces the discoloration & staining and lasts from 6 months to 2 years.
· Braces: The metal braces or, clear plastic molds are used to move teeth gradually. It corrects crooked or, misaligned teeth, thereby improving the health and appearance of a person’s smile. The longevity of this procedure depends on permanent & regular care.
· Veneers: A thin shell of porcelain or, resin composite which covers the front surface of teeth. It corrects the colour and shape of teeth. It lasts from 5 to 15 years.
· Dental Bonding: A resin, matching with the colour of tooth is applied and hardened, thereby bonding the material to the tooth. It also repairs chipped or, cracked tooth, closed gap or, changed shape of tooth. The life after this procedure remains from 7 to 11 years.
· Tooth contouring & reshaping: Here, the length, shape and position of teeth are altered which provides the teeth a natural shape and corrects cracked & chipped teeth. It is used to correct the small imperfection and this is a permanent procedure.
· Dentures: These are set of false teeth and prosthetic devices, constructed to replace missing tooth or, all teeth. The conventional dentures are removable (removable partial denture or complete denture). The life of denture is 5 to 10 years.
· Dental Caps: This also known as Crown which is an artificial tooth shaped structure, placed over week on damaged tooth. It improves the shape, size, strength and appearance of tooth. The life of crown is 5 to 10 years.
· Root Canal Treatment (RCT): This is a common procedure in dentistry where the damaged root of any tooth is treated. It is seen that any injury or, a large cavity, formed due to infection, may extend upto the root of tooth which later becomes severely infected and inflamed too to the extent that the getting RCT is must for patient. Here, first of all, the patient is given anesthesia to numb the infected tooth. Then, an opening is made through the crown of tooth to the pulp chamber. Special type of files are used to clean the infection and unhealthy pulp (out of canals). Initially, certain antibiotic medicines are prescribed to remove infection from root.
Then, the canals are properly reshaped and filled with permanent material, known as ‘gutta-percha’. This helps to keep the canal free from infection and contamination. This type of filling remains intact till permanent filling or, crown is placed. The crown at last is cemented into the place. This is, how the RCT is completed.
The gutta-percha is a hard and tough thermoplastic substance. It is a coagulated latex of certain Malaysian trees, consisting mainly of Hydrocarbon isomeric with rubber and is used in dentistry for filling purposes.
Dental care & precautions:
The dental care is a regular activity of Brushing and Flossing the teeth. The minerals are regularly added to the enamel of tooth and simultaneously they are also lost everyday from enamel layer of a tooth by undergoing 2 processes, namely demineralization and remineralisation. The natural treatment with Flouride (a mineral) occurs through many foods and water.
It is seen specially in old age that the Arthritis in hands and fingers may adversely affect on tooth. The excessive usage of certain drugs also affect oral and dental health.
The main aim to maintain hygine, odourless, fresh and clean mouth is for the sake of improving the longevity of teeth.
The majority of dental treatments are carried out to prevent or treat the two most common oral diseases which are dental caries (tooth decay) and periodontal disease (gum disease or pyorrhea). Common treatments involve the restoration of teeth, extraction or surgical removal of teeth, scaling and root planing and endodontic root canal treatment.
During many dental treatments such as restorative (fillings, crowns, bridges), prosthetic (dentures), endodontic (root canal) therapy, periodontal (gum) therapy, and extraction of teeth, as well as performing examinations, radiographs (x-rays) and diagnosis etc, a dentist can prescribe certain medications also such as antibiotics, sedatives, and any other drugs.
Some dentists may opt for further training after their BDS in order to specialize.
Epidemiology deals with the social health policies, relevant to oral health.
Endodontics a special branch, dealing with Root Canal treatment (RCT).
Conservative dentistry is the art & science of restoring the original shape and function of a tooth which is destructed by carious and non carious lesions. The formation of breakdown/cavity in a tooth due to activities of Bacteria) may affect the tooth/teeth before involvement of pulp or root canal.
Forensic odontology is the gathering and use of dental evidence in law. This may be performed by any dentist with experience or training in this field. The function of a forensic dentist involves basically documentation and verification of identity.
Geriatric dentistry or Geriodontics deals with dental care to older persons, involving diagnosis, prevention, and treatment of problems associated with normal aging and age-related diseases.
Oral and Maxillofacial pathology & implantology is the study, diagnosis, treatment of oral and maxillofacial related diseases, Extractions, implants, and surgery of the jaws, mouth and face.
Orthodontics deals with the straightening of teeth & modification of mid face and mandibular growth.
Pediatric dentistry (pedodontics) it is the Dentistry of children.
Periodontology (periodontics) is the study and treatment of diseases of the periodontium (non-surgical and surgical) as well as placement and maintenance of dental implants.
Prosthodontics (prosthetics) which deals with the Dentures, Bridges and the restoration of implants.