Dental Cariology PDF

Dental Cariology Dr. Donia El-Shafey ‫رؤية ورسالة الكلية‬ Vision “Shaping the future of Dentistry through excellence in Dental Education, innovative Research, patient-centered care, and health promotion Internationally”. ‫الرؤية‬...

Dental Cariology Dr. Donia El-Shafey ‫رؤية ورسالة الكلية‬ Vision “Shaping the future of Dentistry through excellence in Dental Education, innovative Research, patient-centered care, and health promotion Internationally”. ‫الرؤية‬ ‫تشكيل مستقبل طب االسنان من خالل التميز في التعليم الطبي واألبحاث المبتكرة‬.‫والرعاية الصحية التي ترتكز حول المريض وتعزيز الصحة عالميا‬ Mission: “Provide learner-focused dental education, cutting-edge scientific research, patient-centered care, and community engagement all within a positive organizational culture”. :‫الرسالة‬ ‫توفير تعليم طب االسنان الذي يرتكز علي المتعلم والبحث العلمي المتطور والرعاية‬ ‫ كل ذلك في اطار ثقافة تنظيمية‬,‫الصحية المرتكزة علي المريض والمشاركة المجتمعية‬ ‫إيجابية‬ Core Values: Leadership. Excellence. Innovation. Collaboration. Respect. Integrity :‫القيم الجوهرية‬ ‫ النزاهة‬.‫ االحترام‬.‫ التعاون‬.‫ االبتكار‬.‫ التفوق‬.‫القيادة‬ Intended learning outcome (ILOS) Understand dental caries process Understand dental cariology Know the etiology of dental caries Classify dental caries Understand ecology of oral cavity List and distinguish different components of ecosystem Understand the histopathology of dental caries (enamel and dentin) understand caries risk and its assessment tools formulate caries risk assessments Dental caries Dental caries is a multi-factorial infectious microbiological disease. It is a dynamic process taking place in the dental plaque leading to localized demineralization of the inorganic portion and destruction of the organic substances of the tooth. Dental Cariology A discipline dealing with the complex interplay between the oral fluids and the microbial deposits in relation to changes in the hard tooth tissues. Etiology of dental caries Contributing factors of dental caries:The multi-factorial model of dental caries Dental caries is progressive reversible multifactorial, infectious disease of teeth that Caused by complex interaction between acid producing bacteria (mainly streptococcus mutans) with frementable carbohydrates on to tooth surface over time.  The caries balance concept (Proposed by Featherstone) According to the caries balance theory, caries does not result from a single factor; rather, it is the outcome of the complex interaction of pathologic and protective factors. Pathological factors involved in a carious lesion are bacteria, poor dietary habits, and xerostomia. Protective factors include saliva, antimicrobial agents (chlorhexidine, xylitol), fluoride, pit and fissure sealants and an effective diet. Classifications of dental caries  Classifications of dental caries According to their anatomical site According to whether its new or recurrent caries According to the activity of caries lesion According to the speed of progression According to the severity According to their anatomical site Pit and fissure caries: Pit and fissure caries occur on the occlusal surface of posterior teeth, buccal and lingual surfaces of molars, and on palatal surfaces of maxillary incisors. Smooth surface caries: Smooth surface caries occurs on the gingival third of buccal and lingual surfaces and on proximal surfaces. Root caries: When the lesion starts at the exposed root cementum and dentin, it is termed as root caries.  Pits and fissure caries lesion Smooth surface caries lesion Root caries lesion  According to whether its new or recurrent caries Primary caries: It denotes lesions on unrestored surfaces, it constitute the initial attack on tooth surface Recurrent caries: Lesions developing adjacent to fillings are referred to as either recurrent or secondary caries. Residual caries: It is demineralized tissue left in place before a filling is placed.  Primary caries lesion secondary caries lesion  According to the activity of carious lesion Active carious lesion: A progressive lesion is described as an active carious lesion. Inactive/arrested carious lesion: A lesion that may have formed earlier and then stopped is referred to as an arrested or inactive carious lesion. Arrested carious lesion no longer retains food and becomes self- cleansing.  Characteristics of active and inactive caries lesions Activity assessment Likely to be inactive/ Likely to be active factors arrested location Lesion is not in plaque Lesion is in a plaque stagnation area stagnation area (pits/fissure, approximal, gingival) Plaque over lesion Not thick or sticky Thick and/or sticky Surface appearance ,Shiny ,Matt/opaque/loss of luster color: brown-black color: white-yellow Tactile feeling Smooth, hard enamel and Rough enamel /soft dentin dentin Gingival status (if No inflammation, no bleeding Inflammation, bleeding on lesion located near the on probing probing gingiva) Active caries lesion Inactive caries lesion  Inactive caries lesion Active caries lesion  According to the Speed of progression Acute dental caries: Acute caries travels towards the pulp rapidly Rampant caries: It is the name given to multiple active carious lesions occurring in the same patient, frequently involving surfaces of teeth that are usually caries free. It occurs usually due to poor oral hygiene and eating frequent cariogenic snacks and sweet drinks between meals. It is also seen in mouths where there is hyposalivation. Chronic dental caries: Chronic caries travels very slowly towards the pulp. It appears dark in color and hard in consistency. Acute chronic Rapid invading, short duration Dentine is soft in consistency Slow, longer duration Comes out in large flakes Dentine is hard in consistency Light color (yellowish white or Very difficult to excavate yellowish ) Dark color (brown) Painful during excavation Infected by M.O the deepest layer is considered 1. Type of decay: bacteriologically sterile and is rather affected by acid than infected by micro-organisms. Rampant caries According to the Severity Incipient caries: It involves less than half the thickness of enamel Moderate caries: It involves more than half the thickness of enamel,but does not involve dentinoenamel junction. Advanced caries: It involves the dentinoenamel junction and less than half distance to pulp cavity. Severe caries : It involves more than half distance to pulp cavity.  “Ecology” from the greek word “house “ is generally the scientific study of interactions among organisms and their environment ".Regarding the oral cavity, "Ecology of the oral cavity" describes the Ecology interaction between three main components : dental hard tissue , microorganisms and saliva.  Ecosystem 1- Oral environment ecosystem 2- Diet 3- Time 1- Oral environment I-Tooth ecosystem II-Saliva III-Micro- organism I. Tooth Structural Enamel Dentin Cementum Pulp Mechanical Pits and fissure Approximal surface Root surface  Enamel Enamel composed of 95%-98% inorganic component and 3-5% organic structure (by weight percent) Complex It is the hardest structure Nature in human body 343 KHN  The inorganic content of enamel is Hydroxyapatite (HAP), in the way that the calcium, phosphate and hydroxyl ions are arranged in a repeating pattern in the crystal lattice structure. Inclusions of carbonate, sodium, fluoride and other ions make it an impure form of the mineral  Enamel During cavity preparation It is proved that the strongest cavity walls is gained when the enamel rods are constituting the enamel wall of the cavity in full length. Direction of enamel walls should be in the same direction as the enamel rods  Enamel It is Brittle, which looses 85% of its strength after loss of dentin. Therefore, it should be supported against occlusal forces that may lead to its fracture  Dentino-enamel junction Scalloped appearance, provide wider area for stress distribution and stress absorption Intimately bond enamel to dentin, so transfer of stresses from brittle enamel to flexible dentin Most sensitive area due to branching of D.T Hypo-mineralized in relation to Enamel, that’s why there is a rapid lateral spread of caries at DEJ. Therefore, cavity preparation should extend beyond DEJ  Structure of dentin (75% inorganic, 20% organic and 5% water) Heterogeneous structure Act as a cushion for enamel due to its viscoelasticity  Physical properties Color: slightly darker than enamel and is generally light yellowish in young individuals while it becomes darker with age. Thickness: usually more on the cuspal heights and incisal edges and less in the cervical areas of tooth. Hardness: Softer than enamel. Modulus of elasticity: of dentin is low, so it indicates dentin is flexible in nature. The flexibility of dentin provides support or cushion to the brittle enamel and prevents fracture of enamel.  Radius of dentinal tubules and their number/unit area increases towards the pulp (45,000 and wider diameter towards the pulp. 20,000 and smaller diameter near DEJ). So over cutting should be avoided It is sensitive structure and permeable through the D.T. therefore, the molecular weight should be larger than the diameter of the D.T. to be considered biocompatible  Bonding to dentin challenging Heterogenous compositio Complex histological structur Dentinal fluid Dynamic tissu Smear layer e n s e  Types of dentin: Predentin: always present between odontoblasts and dentine as dentin formation is a continuous process throughout life. Mantle dentin: at the outermost layer of the primary dentin, just under the enamel. Circumpulpal dentin: it forms the remaining primary dentin and is more mineralized than mantle dentin. This dentin outlines the pulp chamber and therefore it may be referred to as circumpulpal dentin. Secondary dentin: Physiologic process that occurs by age due to increase in thickness of peritubular and intrratubular dentin, Develops after root formation has been completed and represents the continuing, but much slower, deposition of dentin by odontoblasts. Tertiary dentin It is a localized dentin formed by pathologic process  Reactionary dentine is tubular Reparative dentine and therefore has an dystrophic, shares similar atubular matrix aspects with with cells primary and entrapped in its secondary dentine mineralized matrix Cementum Is a part of the attachment apparatus of the tooth to the alveolar bone § Made by cementoblasts Is the least mineralized of the three dental hard tissues, § Plays no major role in caries disease as it is often abraded at predilection sites in elderly patients. Chemical composition: Inorganic: 50 wt % HAP/FHAP or other impure forms of HAP. Organic: 50 wt% the majority of the organic matrix is composed of collagen. Pulp Chemical composition: 25 wt % organic material and 75 wt % water. The organic content is connective tissue cells (fibroblasts), fibers (collagenous in nature), and ground substances § The pulp is richly vascular; however, this changes with age There are two types of pain arising from the pulp which are mediated by entirely different nerve fibres, each with their own individual characteristics. One is a short, sharp fast pain which is induced by stimuli which cause a rapid fluid flow within the dentinal tubules. Such stimuli include cold, heat, air, drilling, and osmotic stimuli. Once the affected teeth are identified, they can often be treated by sealing the open, exposed dentine. The second type of pain is experienced as a slow, dull, aching, poorly localized pain which is mediated by pain fibres activated by stimuli which are noxious to the pulp, such as prolonged damaging heat and inflammatory mediators. Pain of this character can be difficult to diagnose and often indicates serious pulp damage necessitating removal of the offending pulp by endodontic therapy. Nerve fibre types: A- and C-fibres  NERVE FIBERS ▪ A fibers : acute, sharp, short lasting & localized bearable pain ▪ C fibers : chronic, dull, vague & un localized and unbearable pain A fibers C fibers Närh et al., 2016 I. Tooth Structural Enamel Dentin Cementum Pulp Mechanical Pits and fissure Approximal surface Root surface  Mechanical A pit results from the incomplete union of three enamel lobes during its formation, if complete union happens, the result will be a fossa A Fissure results from the incomplete union of two enamel lobes during the formative period of enamel. If complete union occurs between two enamel lobes, the result will be a groove. The explorer in this case will pass smoothly because there is no defect in the enamel  V-Typeand U-Type : cross-section of fissure is "V" or "U" in shape, shallow in depth, therefore it can be self-cleansable. I and IK -Type : fissure is deeper in a "I" or "K" shape, narrow in width therefore, it is more retentive in structure known as an invasive technique.  There are three features that can influence the development of caries: Approximal 1-Width and location of the contact area. The wider the contact area, the higher the incidence of caries. surface 2-Curvature of proximal surfaces. II. Saliva  Saliva Unstimulated from salivary glands. (Parotid, submandibular, sublingual and minor S.G.). Stimulated Norton V, Lignou S, Methven L. Influence of Age and Individual Differences on Mouthfeel Perception of Whey Protein-Fortified Products: A Review. Foods. 2021 Feb 16;10(2):433. doi: 10.3390/foods10020433. PMID: 33669435; PMCID: PMC7920461. Ducts opening Dynamic and static effect of saliva Static effect: -Effect on bacterial composition of plaque through anti-bacterial factors -Protective effect of pellicle formation -Salivary ions in maintaining super-saturated environment for tooth minerals Dynamic effect: -Clearance of CHO challenges -Alkalinity and Buffering capacity to restore plaque pH to neutrality -Clearance of the acidic products of the plaque metabolism Dynamic effect related to the level of salivary stimulation and are thus activated during eating and drinking Clearance Rate Oral clearance is the dillution and elimination of subtances in the oral cavity. Slow clearance results in pH drop in saliva or plaque and remains for long period, so it is more harmful than a faster clearance rate. It is affected by salivary flow rate and the volumes of saliva in the mouth. So stimulation of salivary secretion will increase the clearance rate (e.g: gum-chewing). :  2. Electrolyte ( calcium, inorganic phosphates, bicarbonates, fluoride): 1-Maintain supersaturation of Calcium and Phosphate ions in saliva (remineralization). 2-Buffering action (pH neutralization) s 3. Buffering Action of Electrolytes A buffer is a substance which resist changes in pH. In the development of caries there are two main buffer systems: Phosphate System: at pH 7.5 to 6, phosphate is present as dihydrogen and monohydrogen phosphate which exchange H+ ions. When pH decreases, H+ increases, and binds with mono hydrogen forming dihydrogen phosphate ions. Thus no further drop in the pH. H+ +HPO2-4H2PO4- Bicarbonate System: Works with stimulated saliva, bicarbonate ions increase with increasing flow rate so more Carbon dioxide is released which boosts the buffering capacity of thesystem. H+ +HCO3--H2CO3CO2 +H2O 4. Organic components FUNCTIONS 1-Participating in Enamel Pellicle formation. 2-Mucosal Coating. 3-Anti-microbial defense 4-Digestive actions. Hyposalivation: When the flow rate is less than 0.1 ml per minute, and when the stimulated flow rate is less than 0.7 ml per minute. Causes : 1-Medications: eg; antidepressants and diuretics Xerostomia:sensation of oral dryness that impairs the oralfunctions. Saliva is the 2-Radiation liquid of the oral cavity which reduces 3-Autoimmune diseases: eg; AIDS dissolution of the dental hard tissue by its 4-Menopause clearance ability, by means of its content of electrolytes and antimicrobials. 5-Eating disorders Hyposalivation and Xerostomia will 6-Salivary gland stones therefore increase the risk of caries formation