Hard Tissue Examination of Dentition

Hard Tissue Examination of the Dentition

• Children need to have their first dental examination no later than 6 months after the eruption of the first tooth, and before their first birthday.

The Teeth

• The clinical crown is the part of the tooth above the attached periodontal tissues and are visible.
• The clinical root is the part of the tooth not visible.

The Dentitions

• Primary dentition begins in utero.
• Mixed or transitional dentition occurs around ages 6-12.
• Permanent dentition is considered adult dentition.

Developmental Enamel Lesions

• Enamel Hypoplasia is a defect due to a disturbance during the formation of the enamel matrix.
  • Can be genetic or systemic.
  • Enamel Hypoplasia may appear white, yellow, or brown.
  • Commonly appears on first molars, incisors, and canines.
  • Can be local or generalized.

Developmental Defects of Dentin

• Genetic Dentinogenesis imperfecta is the most common type, resulting in rapid wear and attrition of the teeth.
  • Gives off an Opalescent brown discoloration in appearance.

Non-carious Dental Lesions

• These lesions result from loss of tooth structure near the cementoenamel junction.

Attrition

• The wearing away of a tooth as a result of tooth-to-tooth contact.
• It occurs on the location of the tooth.
• The Etiology is from bruxism or habits.
• Appears as a small shiny, flat, worn spot.
• Slight: just within the enamel.
• Moderate: dentin is showing.
• Severe: with pulpal shadowing.

Erosion

• The loss of tooth substance via chemical process (acid) that does not involve known bacterial action.
  • This usually occurs on facial and lingual surfaces.
  • Smooth, shallow, hard, shiny.

Abrasion

• The mechanical wearing away of tooth substance by forces other than mastication
  • Presents typically on exposed root surfaces, and is v- or wedge shaped.
    • This occurs via aggressive brushing.

Abfraction

• The means to break away and results from microfractures in the hydroxyapatite crystals of enamel and dentin.
  • Appear as a V- or wedge shaped with hard, smooth, shiny surface
  • A multifactorial occurrence.

Fractures of the Teeth

• Can occur due to trauma, horizontal/diagonal/vertical impact or by filling/crown/non-restorative practices.

Dental Caries

• Dental Caries development involves microorganisms, fermentable carbohydrate, and a susceptible tooth surface.
  • Carious Lesions are classified by G.V. Black's Classification (most commonly used), International Caries Classification and Management System, and American Dental Association Caries Classification System.
  • Consist of Pit and Fissure, Smooth Surface, Primary, Recurrent, Arrested - hard surface dark brown or reddish-brown color, and Rampant

G.V. Black's Classification

• Class I Caries affects pits and fissures on the occlusal third of molars and premolars, occlusal two-thirds of molars and premolars, and the lingual part of anterior teeth.
• Class II Caries affects proximal surfaces of molars and premolars.
• Class III Caries affects proximal surfaces of central incisors, lateral incisors, and cuspids without involving the incisal angles.
• Class IV Caries affects proximal including incisal angles of anterior teeth.
• Class V Caries affects gingival one-third of facial or lingual surfaces of anterior or posterior teeth.
• Class VI Caries affects cusp tips of molars, premolars, and cuspids.

Enamel Caries

• Stages in the Formation of a Carious Lesion
  • Incipient: demineralization, no breakthrough enamel, appears white.
  • Untreated: visible

Early Childhood Caries

• Due to high levels of S. mutans.
  • Demineralization begins along the cervical third of the maxillary anterior teeth as white spot lesions
  • Causes: Prolonged breast feeding, bottles that contain milk, items dipped in sugar.

Root Caries

• Lesion that affects the cementoenamel junction and typically occurs on exposed root surfaces
  • Appears light/dark brown or black.
  • Risk Factors: Age, Poor biofilm removal, Medications, Open contacts, Partial Clasps

Occlusion

• Class I Normal Occlusion (Class I)
  • Molar relation: The mesiobuccal cusp of the maxillary first permanent molar occludes with the buccal groove of the mandibular first permanent molar.
  • Canine Relation: The maxillary permanent canine occludes with the distal half of the mandibular canine and the mesial half of the mandibular first premolar.
• Class II Distocclusion:
  • Molar relation: The buccal groove of the mandibular 1st molar is distal to the MB cusp of the maxillary 1st molar.
  • Division I: Mandible is retruded and all maxillary incisors are protruded.
  • Division II: Mandible is retruded and one or more maxillary incisors are retruded.
• Class III
  • Molar relation: The buccal groove of the mandibular first permanent molar is mesial to the mesiobuccal cusp of the maxillary first permanent molar by at least the width of a premolar.
  • Canine relation: The distal surface of the mandibular canine is mesial to the mesial surface of the maxillary canine by at least the width of a premolar.
• The abnormal alignment of the upper and lower teeth; Misaligned teeth can happen as teeth develop or from childhood habits, such as thumb sucking.
• Most common cause is when the jaw is too small compared with the size of the teeth

Malrelations of Groups of Teeth

• Posterior Crossbite
  • Maxillary or mandibular molars are either facial or lingual to their normal position
• Anterior crossbite
  • Maxillary anterior teeth are lingual to mandibular anterior teeth
• Edge-to-edge
  • Incisal surfaces of maxillary anterior teeth occlude with incisal surfaces of mandibular teeth
• End-to-end
  • Molars and premolars occlude cusp-to-cusp as viewed mesiodistally
• Open bite
  • Lack of occlusal or incisal contact between certain maxillary and mandibular teeth because either or both have failed to reach which should result in the line of occlusion. - The teeth cannot be brought together, and a space remains as a result of the arching of the line of occlusion
• Overjet
  • The horizontal distance between the labioincisal surfaces of the mandibular incisors and the linguoincisal surfaces of the maxillary incisors - Measured in mm
• Underjet
  • Maxillary teeth are lingual to mandibular teeth. Measurable horizontal distance between the labioincisal surfaces of the maxillary incisors and the linguoincisal surfaces of the mandibular incisors. Measurement of horizontal distance btwn incisors. - Measured in mm
• Overbite
  • Vertical overlap, the vertical distance by which the maxillary incisors overlap the mandibular incisors - Normal overbite: 1/3 - Moderate overbite: middle 1/3 - Deep (severe) - Measured in mm
• Abormal Displacements
  • Labioversion: A tooth that has assumed a position labial to normal
  • Lingoversion: Tooth position is lingual to normal.
  • Buccoversion: Tooth position is buccal to normal.
  • Supraverion: Elongated above the line of occlusion.
  • Infraversion: Tooth is depressed below the line of occlusion
  • Torsiversion: Tooth is turned or rotated

Trauma from Occlusion

• Primary occlusal trauma results from excessive occlusal force on a tooth with normal bone support.
• Secondary occlusal trauma results when normal or abnormal occlusal forces are placed on a tooth with bone loss and inadequate alveolar bone support.

Recognition of Signs of Occlusal Trauma

• Mobility
• Drifting
• PDL
• Thickening of the lamina dura
• Root resorption

Study Models

• Purpose is to provide a life-size reproduction of the teeth, gingiva, and adjacent structures and used To aid in the assessment and care of a patient.

Dental Biofilm and Other Soft Deposits

• Soft deposits include acquired enamel pellicle, microbial (bacterial) biofilm, materia alba, and food debris.
  • Dental biofilm poses a primary risk for gingivitis, periodontal disease, and caries. - Periodontal disease and dental caries do not cause each other. - Dental Biofilms are transmissible.

Acquired Pellicle

• Is a thin acellular tenacious film formed of proteins, carbohydrates, and lipids
  • Types of Pellicle: - Supragingival: clear, not visible to the eye, can been seen with disclosing agent - Subgingival: continuation of supra, embeds with tooth structure - Forms on restorations, crowns, tooth surface, dentures, mouthguards, calculus, ortho appliances
  • Forms within mins (fully 30-90 min)
  • Significance of Pellicle: - Protection - Important role in the maintenance of oral cavity - Lubricates – keeps the surfaces moist, prevents drying - Nidus (to multiply) of attachment for bacteria – participates in biofilm formation - Mode for calculus attachment, can Extrinsic stain – gradually can become brown, grey, or other colors

Removal of Pellicle

• Abrasive toothpastes, whitening products, and Acidic foods/drinks

Stages of Dental Biofilm Formation

• Stage 1: Formation of planktonic (white blood cells)
• Stage 2: Bacterial Multiplication and Colonization
• Stage 3: Matrix Formation
• Stage 4: Biofilm Growth
• Stage 5: Maturation

Changes in Biofilm Microorganisms

• Days 1-2 consists of gram-positive cocci
• Days 2-4 (72 hours capable of initiating the inflammatory process)
• Days 6-10 consists of gram-negative anaerobic bacteria
• Days 10-21 (2-3 weeks gingivitis develops)

Supragingival and Subgingival Dental Biofilm

• Supragingival Biofilm
  • Made up of 2 layers - Gram-positive aerobic bacteria - First layer is composed of streptococci on the coronal to the gingival margin
• Subgingival Biofilm
  • Made up of 4 layers - Gram-negative anaerobic bacteria - First layer is composed of Actinomyces between the periodontal attachment and the gingival margin

Composition of Dental Biofilm

• 20% of the biofilm are organic and inorganic solids with the other 80% being water.
  • Consists of inorganic elements Calcium and Phosphorus, and Fluoride
  • Organic Elements consist of Carbohydrates and Proteins

Clinical Aspects of Dental Biofilm

• Consists of Supragingival being Coronal to the gingival margin, and Subgingival located between the epithelial attachment and the gingival margin (within the sulcus or pocket)
  • Detection of Biofilm requires Direct vision, the use of an Explorer, or a Disclosing agent
    • Detection of Biofilm requires Direct vision, the use of an Explorer, or a Disclosing agent

Significance Of Dental Biofilm

• Major role in the initiation and progression of dental caries and periodontal diseases (non-transmissible)
  • Significant in the formation of dental calculus, which is essentially mineralized dental biofilm.

Dental Caries (Critical pH levels)

• Cariogenic Microorganisms in Biofilm include Mutans streptococci & Mutans streptococci
• Critical pH for inEnamel demineralization averages 4.5 - 5.5
• Critical pH for dentin (root surface) demineralization 6.0-6.7

Materia Alba

• Soft, loosely attached, whitish tooth deposit that is clinically visible with a cottage Cheese-like texture and white or grayish-white in appearance.
  • An unorganized accumulation of living and dead bacteria, epithelial cells, leukocytes, salivary proteins, and food debris. - Removed with a water spray, oral irrigator, or tongue action

Calculus

• Dental biofilm mineralized by crystals of calcium & phosphate witha hard, tenacious mass forms on the clinical crowns of natural teeth, dental implants, dentures and other dental prostheses - Calcium formation occurs in 3 steps: - 1st step: pellicle formation, 2nd step: biofilm formation, and a 3rd step: mineralization
  • Also affected by Calculus formation is affected by factors such as salivary flow, salivary supersaturation with calcium phosphate salts, and inhibitors and promoters of calculus formation - crystal formation consists of crystal formation, namely, hydroxyapatite, octacalcium, calcium phosphate, whitlockite, and brushite.
  • Calculus is considered a predisposing factor to perio pocket formation
    • Cornerstone of nonsurgical periodontal therapy is the daily control of biofilm by the patient, supplemented by definitive professional calculus removal, to reduce or eliminate gingival inflammation and bleeding on probing.

Location of Calculus

• Most frequent Supragingival cases are on the mandibular anterior teeth & facials of maxillary 1st and 2nd molars.
• Subgingival Clinical crown is apical to the gingival margin (CEJ/pocket formation) and can be Generalized or localized in the root.

Composition of Calculus

Inorganic Content: Includes Calcium (CA), Phosphorus (P), Carbonate (CO3), Sodium (NA), Magnesium (Mg) .

• Fluoride is higher in subgingival than supragingival calculus higher

Crystals

• 2/3 of the inorganic content is crystalline (apatite)
• Dental enamel is the most highly mineralized tissue in the body with 95-97% inorganic salts. - Dentin is ~65% inorganics. - Cementum and bone 45-70% inorganic. - Mature calculus ~ 70-80%

Mechanism of Mineralization

• Heavy calculus formers have higher salivary levels of calcium and phosphorus than do light calculus formers -
• Light calculus formers have higher levels of pyrophosphate
• Mineralization can begin as early as 24 to 48 hours when a patient's personal daily oral hygiene is inadequate · supersaturation of saliva and plaque biofilm is the driving force for mineralization. -Calculus inhibitors for supragingival calculus include pyrophosphate and zinc salts . - Mineralization can begin as early as 24 to 48 hours when a patient's personal daily oral hygiene is inadequate - Calculus formation increases with age

Structure, Attachment, and Clinical Characteristics of Calculus

• Surface of a calculus mass is typically rough and detectable with the use of an explorer or probe
• Easy or difficulty of removing calculus relates to the manner of attachment to the tooth surface and removal from Dentin irregularities(cracks lamella carious defect by mechanical locking into undercuts) Difficult to be certain all calculus is removed by this method

Managing Calculus

• Calculus Control includes Regular Professional Continuing Care and to use Anticalculus Dentifrice and.
• Chemoterapeutic Anticalculus Agents (used in "tartar/control" mouthrinses or dentifrices) are mineralization inhibitors such as pyrophosphates, zinc citrate, and pyrophosphates plus triclosan.
  • Only products with the ADA seal of acceptance should be recommendations.

Dental Stains & Discolorations

• Occurs when they Adhere directly to surfaces, are contained within calculus and soft deposits, or are incorporated within tooth structure or restorative material.

• Significance of stain is primarily the appearance or cosmetic effect: -- Extrinsic occurs on the external surface of the tooth and may be removed by procedures of toothbrushing, scaling, and/or polishing; Origins are metallic and nonmetallic

• Intrinsic occurs within the tooth surface and CANNOT be removed by scaling or polishing, although their effects may be improved by certain whitening procedures

Extrinsic Stains

• Most frequently observed stains are coffee, tea, and tobacco, bacteria, food debris, and some medications.
• Yellow Stain is often localized/generalized and is often influenced by diet and age
• Green Stain can occur due to poor oral hygiene, dental biofilm retention, chromogenic bacteria, and gingival hemorrhage

Black-Line Stain

• Black-line stain is a highly retentive black or dark brown that forms along the gingival third near the gingival
• No definitive etiology -actinomyces and dietary habits

Tobacco Stain

• Caused by cigarettes, pipe, cigars, smokeless tobacco: can appear light brown to dark leathery brown or black
  • commonly appears Cervical 1/3 primary on the lingual surfaces
  • Commonly caused by tar

Brown Stains

• Brown Pellicle can stain certain various colors that result from chemical alteration of the pellicle (tea, coffee, soy sauce) that occur in the presence of Stannous Fluoride and Antimicrobial Agents - Chlorhexidine, alexidine, essential oil/phenol, and cetylpyridinium chloride that are used in mouthrinses and are effective against biofilm formation

Metallic Stains

• Metals or Metallic Salts from Metal-Containing Dust of Industry and Metallic Substances are Contained in Drugs.
  • Iron, Nickel, Cadmium, and Copper all cause different colored stains.

Intrinsic Stains; Disturbances in Tooth Development

• Enamel hypoplasia is often caused by by damage to the tooth germ during development and the location of the defect and related to timing of the injury during development White spots, pits, or grooves arise due to ameloblastic disturbance teeth

Dental Fluorosis

• Results in Enamel hypomineralization by ingestion of excessive fluoride ion from any source during the period of mineralization caused by Chalky white spots to brown

Drug-Induced Conditions

• The use of antibiotic can result in a greenish discoloration
• TetracyclineDiscoloration of a child's teeth when the drug is administered to the mother during the third trimester of pregnancy or to the child in infancy and early childhood.
• Exogenous Intrinsic Stains
  • Occur when intrinsic stains come are external to the tooth:
    • Tobacco stains, and from Silver Nitrate, Restorative material and Amalgam