Introduction to Dentistry PDF

Introduction to dentistry Presented by: Dr. Amr Sharawy Associate professor of dental materials What is Dentistry? It is the art and science dealing with diagnosis, treatment and prevention of diseases affecting hard and soft dental and oral tissues. Examples of hard tissues: Te...

Introduction to dentistry Presented by: Dr. Amr Sharawy Associate professor of dental materials What is Dentistry? It is the art and science dealing with diagnosis, treatment and prevention of diseases affecting hard and soft dental and oral tissues. Examples of hard tissues: Teeth and bone. Examples of soft tissues: Lips, cheeks, tongue and gingiva. Objectives of dentistry: 1-To relief Pain 2-Diagnosis and treatment of oral diseases 3-To restore function → Maintain masticatory efficiency → Speech 4-To restore esthetics → Simulate the natural appearance of the patient → Beautify the existing condition  Divisions of dental schools Academic Clinical ↓ ↓ 1-Dental biomaterials 1)Oral Medicine and Diagnosis 2)Periodontology 2-Dental anatomy 3- Oral Biology 3) Oral radiology (X-ray) 4) Operative dentistry 4) Oral Pathology 5) Endodontics 6) Oral Surgery 7) Fixed prosthodontics 8) Removable Prosthodontics 9) Pedodontics 10) Orthodontics  Academic divisions 1-Dental biomaterials : It is an academic science which studies composition, manipulation, properties, behavior and applications of all materials used in dental clinics and laboratories. N.B.: Materials placed in the oral cavity come in contact and interact with living tissues. Therefore, they must be biocompatible. i.e. they should not be toxic, irritant or harmful and they should not undergo tarnish and corrosion. 2-Dental Anatomy Tooth consists of: → Crown. → Root(s). Number of teeth: → Permanent (Adults): 32 teeth, 16 upper and 16 lower, 8 in each quadrant. → Deciduous (Children): 20 teeth, 10 upper and 10 lower, 5 in each quadrant. Functions of teeth : 1) Speech. 2) Mastication: o Incisors → incision (cutting). o Canines → tearing. o Premolars & molars → grinding. 3) Esthetics: o Support facial expressions. o Provide good esthetics when they are in normal shape, contour, color and arrangement. Arrangement and nomenclature of teeth: a. Permanent teeth: Arrangement: Anterior teeth→ Incisors →Central Incisor → Lateral Incisor → Canines Posterior teeth → Premolars →2 (1st premolar & 2nd premolar) → Molars →3 (1st molar, 2nd molar & 3rd molar" wisdom tooth") b. Deciduous teeth: Arrangement: Anterior teeth→ Incisors → Central Incisor → Lateral Incisor → Canines Posterior teeth → Molars →2 (1st molar & 2nd molar)  3-Oral biology: It is the branch of dentistry that deals with the study of soft and hard normal tissue on microscopic level. 4- Oral Pathology: It is the branch of dentistry concerned with the diseases of oral and paraoral structures, including oral soft tissues, mucous membranes, teeth, jaws, and salivary glands.  Clinical divisions 1)Oral Medicine and Diagnosis Oral Medicine→it is the branch of dentistry that involves detecting & treating diseases affecting the different oral structures (tumor, cyst, etc.). Diagnosis → it is the use of scientific knowledge to identify oral diseases and to distinguish one disease from another. 2)Periodontology: Periodontology→ it is the branch of dentistry concerned with the health of tooth supporting structures. i.e. gingiva, cementum, alveolar bone and periodontal ligament. e.g.: Gingivitis: - Inflammation of the gingiva. When the severity of inflammation increases, it may lead to gingival recession, bone resorption and formation of pockets. 3-Oral Radiology: It is the specialty of dentistry concerned with the production of images using radiant energy and interpretation of these radiographic images to obtain data that can be used in the diagnosis of diseases and disorders of the oral and maxillofacial structures. -It is considered as the dentist's 3rd eye. -It is a diagnostic tool used to examine embedded structures e.g. roots number and form, number of root canals, periapical area, impacted teeth. It also helps in the diagnosis of jaw fractures and interproximal caries. jaw fracture impacted teeth interproximal caries N.B.: Structures that are seen in the x-ray are referred to as radio-opaque. They appear white in the x-ray. This radio-opacity is caused by absorption of x-rays by the mineral content of these structures. Examples of radio-opaque structures in the X-ray films are: -Enamel. -Dentin. -Cementum. -Bone. -Structures not seen in the x-ray film are referred to as radiolucent. They do not absorb the x-rays so they appear black. Examples of radiolucent structures in the oral X-ray films are: -Pulp. -Periodontal ligament. -Dental Caries. -Ideally, restorative materials should be radiopaque so that recurrent caries under them can be detected. 4-Operative Dentistry: It is the art and science that deals with diagnosis and treatment of defects of the tooth structure such as dental caries. Dental caries: It is an irreversible bacterial disease of hard dental tissues (Enamel, Dentin and Cementum) caused by demineralization of the calcified tissues. Food Debris+ Bacteria → acids which will act on the tooth structure→ Caries Caries is classified according to the area of the tooth where it occurs (G.V. Black's classification): Class I: -Pit & Fissure Caries occur in occlusal surface of posterior teeth -Occlusal 2/3 of buccal (or palatal) surfaces of posterior teeth. -Palatal surface of upper lateral incisor Class II: Smooth surface caries occurring in the proximal surface (Mesial or Distal) of Posterior teeth Class III: Smooth surface caries limited to the proximal surface of anterior teeth NOT involving the incisal edge Class IV: Smooth surface caries affecting proximal surface of anterior teeth involving incisal angle. Class V: Smooth surface caries affecting gingival 1/3 of facial (labial or buccal & lingual or palatal) surfaces of all teeth (except palatal surface of 2/2). Class VI: Caries occurring in any site other than the 5 classes e.g: Cusp tip, Root Caries,………………. l  Management of caries: Once caries occurs, it will proceed further and the tooth won't be able to regenerate. Thus, caries has to be removed by preparing a cavity in the tooth. This cavity is then filled with a filling material (restorative material). Filling materials maybe →Metallic e.g. Amalgam. →Non-metallic e.g. Composite. Amalgam Composite 5-Endodontics: It is that branch of dentistry concerned with the morphology, physiology and pathology of the human dental pulp and periapical tissues. -In endodontic treatment, the pulp is removed using a serrated needle like instrument available in different sizes. After the canals are cleaned using endodontic instruments (files or reamers), the canals are filled with endodontic filling material which may be either: →Metallic: Silver points. →Non-metallic: Polymer called Gutta Percha together with sealer. Cleaning the root canal with endodontic Filling the root canal with Gutta Percha. instrument. 6-Oral Surgery: It is the branch of dentistry dealing with diagnosis, surgical and adjunctive treatment of diseases, defects and injuries of the human jaws and associated structures e.g. Extraction of teeth, Surgical removal of tumors, Management of jaw fractures and Treating tempromandibular joint problems etc.  Prosthodontics: It is that branch of dentistry dealing with restoration and replacement of teeth by artificial devices. Prosthodontics may be either fixed prosthodontics or removable prosthodontics. Prosthesis: artificial appliance restoring a missing part of the body e.g.: Limb, nose, tooth etc. -According to the number of teeth present in the patient's mouth, patients may be classified into: Dentulous → all teeth are present. Edentulous → all teeth are missing. Partially edentulous → some teeth are present & some are missing. 7-Fixed prosthodontics : A subdivision of prosthodontics that focuses on restoration and replacement of teeth by fixed artificial restoration. a. Crown: Fixed artificial restoration of the coronal portion of the natural tooth restoring function & esthetics. Indications: 1. Endodontically treated teeth (Non-vital). 2. Badly broken down teeth. 3. Discolored or esthetically displeasing teeth. A tooth reduced to receive a crown b. Bridge: Fixed artificial restoration replacing one or more missing teeth. Indications: To replace one or more missing teeth. Components of bridge: Retainer: It is that part of the bridge that covers the adjacent natural tooth (abutment) & helps bridge fixation. Pontic: It is that part of bridge that replaces the missing tooth or teeth. Solder joint (Connector): It is that part of the bridge that holds all bridge units together. According to their material, crowns and bridges may be: Metallic → Nickel Chromium (Ni-Cr) or gold alloys. Non-metallic→ Porcelain or acrylic resin Combination of metal and non-metal: To mask the metallic color of metals and to increase the strength of the non-metal. N.B.: The abutment is the natural tooth which is prepared to receive the retainer. In order for the tooth to receive a crown or retainer, it is reduced in size by removal of the area of height of contour (Tooth Reduction). For the dental laboratory to construct any oral prosthesis, it should have an exact replica of the oral structures called the cast. The cast is obtained by making an impression and pouring it. Taking an impression After selection of suitable tray: 1, 2: Mixing of liquid and powder. 6: Removal from patient’s mouth. 3, 4: Filling up the tray. 7: Rinsing with water. 5: Insertion in patient's mouth till it hardens. 1 2 3 4 5 6 7 8 Pouring of dental stone to prepare cast: 1 2 3 4 5 6 7 8 8-Removable Prosthodontics: A subdivision of prosthodontics that focuses on restoration and replacement of teeth by removable artificial restorations. e.g. complete and partial dentures. A)Complete Denture: It is a removable artificial restoration restoring all natural teeth in B)edentulous patients. Components of complete denture: 1) Artificial teeth →Porcelain →Acrylic Resin 2) Denture Base → Metallic (Co-Cr alloy) →Non Metallic (Acrylic Resin) Denture Base Artificial teeth N.B.: The use of dental implants has developed as a treatment modality for partially (and fully) edentulous patients. Implants are made from Titanium (Ti) or Titanium alloys as they are biocompatible materials. 9-Pedodontics: Child; children: pedo Is that branch of dental science which deals with the guidance of the primary and young permanent dentition in growth and development as well as the prevention and treatment of pathologic oral conditions which may occur during childhood. 10-Orthodontics: It is the specialty of dentistry that is concerned with the study and treatment of malocclusions, which may be a result of tooth irregularity, disproportionate jaw relationships, or both. This can be achieved either by removable appliances (made of Acrylic resin) or by fixed appliances (brackets, bands, wires).