Oral Pathology 1 Lecture 8 PDF

Oral pathology 1 MAJD & SHATHA Lecture 8 BY : MAJD & SHATHA ORAL PATHOLOGY 1 LECTURE : 8 0 Oral pathology 1 MAJD & SHATHA Lecture 8...

Oral pathology 1 MAJD & SHATHA Lecture 8 BY : MAJD & SHATHA ORAL PATHOLOGY 1 LECTURE : 8 0 Oral pathology 1 MAJD & SHATHA Lecture 8 ABNORMALITIES OF TEETH I II ENVIRONMENTAL ALTERATIONS OF TEETH DEVELOPMENTAL ALTERATIONS OF TEETH - Environmental effects on tooth structure development - Developmental alterations in the number of teeth - Post-developmental structure loss - Developmental alterations in the size of teeth - Environmental discolorations of teeth - Developmental alterations in the shape of teeth - Localized disturbances in eruption - Developmental alterations in the structure of teeth 1  Oral pathology 1 MAJD & SHATHA Lecture 8 ENVIRONMENTAL ALTERATIONS OF TEETH LOCALIZED DISTURBANCES IN ERUPTION  Delayed Eruption  Emergence is the moment of eruption when the first part of the cusp or crown is visible through the gingiva.  This process normally occurs when the dental root is approximately two-thirds its final length.  Emergence occurs over a broad age range and differs according to gender and race.  Eruption is considered delayed if emergence has not occurred within 12 months of the normal range or by the time 75% root formation is complete.  Eruption can be delayed due to local or systemic conditions. 2 Oral pathology 1 MAJD & SHATHA Lecture 8  LOCAL CONDITIONS ASSOCIATED WITH DELAYED ERUPTION  Ankylosis of deciduous tooth  Mucosal barriers, such as scar tissue  Arch-length deficiency  Oral clefts  Ectopic eruption  Premature loss of deciduous tooth  Enamel pearls  Radiation damage  Failure of resorption of deciduous tooth  Regional odontodysplasia  Gingival fibromatosis or hyperplasia  Segmental odontomaxillary dysplasia  Impaction of deciduous tooth  Supernumerary teeth  Injury or infection of deciduous tooth  Tumors, odontogenic and non-odontogenic  SYSTEMIC CONDITIONS ASSOCIATED WITH DELAYED ERUPTION  Anemia  Heavy metal intoxication  Celiac disease  Human immunodeficiency virus (HIV)infection  Cerebral palsy  Ichthyosis (a group of genetic skin diseases)  Chemotherapy  Inadequate nutrition  Dysosteosclerosis (a bone disease  Low birth weight  Drugs, such as phenytoin  Renal failure  Endocrine disorders (e.g., hypothyroidism,  Tobacco smoke hypopituitarism, hypoparathyroidism,  Vitamin D–resistant rickets pseudohypoparathyroidism)  Genetic disorders 3  Oral pathology 1 MAJD & SHATHA Lecture 8  Clinical and Radiographic Features  Failure of eruption may be localized or generalized.  In many localized examples, the cause is readily apparent upon radiographic examination when objects are discovered in the path of eruption.  In other cases, the cause is not obvious and may be discovered after surgical exploration.  Generalized delayed eruption often is more problematic and frequently is associated with a systemic disorder.  Treatment and Prognosis  For localized delayed emergence, removal of any pathosis in the path of eruption may be sufficient to allow eruption to occur.  If eruption does not proceed: surgical exposure accompanied by orthodontic traction.  In generalized delayed eruption: evaluation of patient for systemic diseases known to be associated with the process.  Successful resolution of the underlying disorder often is followed by completion of eruption. 4  Oral pathology 1 MAJD & SHATHA Lecture 8  Premature Eruption  Teeth may be present at or shortly after birth, before the normal time for eruption.  Teeth present in newborns are called natal teeth.  Those arising within the first 30 days of life are designated neonatal teeth.  Some of these teeth may represent predeciduous supernumerary teeth, but most are prematurely erupted deciduous teeth (not supernumerary teeth).  Approximately 85% of natal teeth are mandibular incisors, followed by maxillary incisors, and posterior teeth.  Treatment and Prognosis  Natal and neonatal teeth must be approached individually with sound clinical judgment guiding appropriate therapy.  Radiographs may be difficult to obtain but could be helpful in distinguishing premature eruption of a deciduous tooth from a supernumerary tooth.  Since the prematurely erupted teeth in most cases represent the deciduous dentition, removal should not be performed hastily. 5  Oral pathology 1 MAJD & SHATHA Lecture 8  However, lack of root formation in these teeth may cause mobility and some of them are lost spontaneously.  If the teeth are mobile and at risk for aspiration, removal is indicated.  If the teeth are stable, then they should be retained.  Traumatic ulcerations of the adjacent soft tissue may occur during breast feeding but often can be resolved with appropriate measures.  Impaction  Teeth which remain unerupted or partly erupted beyond the normally expected time.  Some authors subdivide these non-erupted teeth into: 1) Impacted teeth: those that are obstructed by a physical barrier. 2) Embedded: those that appear to exhibit a lack of eruptive force.  Clinical and Radiographic Features  Impaction of deciduous teeth is extremely rare.  When seen, it most commonly involves second molars.  Ankylosis plays a major role in the pathogenesis.  In the permanent dentition, the most frequently impacted teeth are the mandibular third molars, followed by maxillary third molars and maxillary canines, and mandibular premolars. 6  Oral pathology 1 MAJD & SHATHA Lecture 8  In the permanent dentition, the most frequently impacted teeth are the mandibular third molars, followed by maxillary third molars and maxillary canines, and mandibular premolars.  Lack of eruption most frequently is caused by crowding and insufficient maxillofacial development.  Impacted teeth are frequently diverted or angulated and eventually lose their potential to erupt (on completion of root development).  Other factors known to be associated with impaction include the following:  Overlying cysts or tumors.  Trauma.  Reconstructive surgery.  Thickened overlying bone or soft tissue.  Systemic disorders, diseases, and syndromes.  Impacted teeth may be partially erupted or completely encased within the bone (i.e., full bony impaction).  The impaction may be classified according to the angulation of the tooth in relationship to the remaining dentition: mesioangular, distoangular, vertical, horizontal, or inverted.  On occasion, a small spicule of nonvital bone may be seen radiographically or clinically overlying the crown of partially erupted permanent posterior tooth (termed an eruption sequestrum). 7  Oral pathology 1 MAJD & SHATHA Lecture 8  Treatment and Prognosis  The choices of treatment for impacted teeth include the following:  Long-term observation without intervention.  Orthodontically assisted eruption, e. g. impacted maxillary canines.  Transplantation: in case of extraction of other teeth.  Surgical removal: presence of infection, non-restorable carious lesions, cysts, tumors, or destruction of adjacent tooth and bone.  Because of the frequent occurrence of significant pericoronal inflammation (pericoronitis), specialists often recommend extraction over close observation of impacted teeth.  The risks associated with non-intervention include the following:  Crowding of dentition  Resorption, caries, and worsening of the periodontal status of adjacent teeth.  Development of pathologic conditions, such as infections, cysts, and tumors. 8  Oral pathology 1 MAJD & SHATHA Lecture 8 The risks of intervention include the following:  Transient or permanent sensory loss  Alveolitis  Trismus  Infection  Fracture  Temporomandibular joint (TMJ) injury  Periodontal injury  Injury to adjacent teeth 9  Oral pathology 1 MAJD & SHATHA Lecture 8  Ankylosis  Eruption continues after the emergence of the teeth to compensate for masticatory wear and the growth of the jaws.  The cessation of eruption after emergence is termed ankylosis and occurs from an anatomic fusion of tooth cementum or dentin with the alveolar bone.  Other terms for this process include infraocclusion, secondary retention, submergence, reimpaction, and reinclusion.  Normally, the periodontal ligament might act as a barrier that prevents osteoblasts from applying bone directly onto cementum.  Ankylosis could arise from a variety of factors that result in a deficiency of this natural barrier such as trauma and even genetic factors. 10  Oral pathology 1 MAJD & SHATHA Lecture 8  Clinical and Radiographic Features  Ankylosis may occur at any age.  Clinically the condition is most obvious if the fusion develops during the firsttwo decades of life because it causes alterations in occlusion.  The most commonly involved teeth in order of frequency are:  mandibular primary first molar.  mandibular primary second molar.  maxillary primary first molar.  maxillary primary second molar.  Ankylosis of permanent teeth is uncommon.  In the deciduous dentition, mandibular teeth are affected ten times as often as the maxillary dentition.  The occlusal plane of the involved tooth is below that of the adjacent dentition (infraocclusion) in a patient with a history of previous full occlusion.  Radiographically, absence of the PDL space may be noted; however, the area of fusion is often in the bifurcation and interradicular root surface, making radiographic detection most difficult. 11  Oral pathology 1 MAJD & SHATHA Lecture 8  Ankylosed teeth that are allowed to remain in position can lead to a number of dental problems:  Adjacent teeth often incline toward the affected tooth, subsequent occlusal and periodontal problems may occur.  The opposing teeth often exhibit overeruption.  Occasionally, the ankylosed tooth leads to a localized deficiency of the alveolar ridge or impaction of the underlying permanent tooth.  An increased frequency of lateral open bite and crossbite is seen.  Treatment and Prognosis  Because they are fused to adjacent bone, ankylosed teeth fail to respond to orthodontic forces.  Recommended therapy for ankylosis of primary molars is variable and  is determined by the severity and timing of the process. When an underlying permanent successor is present, extraction of the ankylosed primary molar at the proper time usually allows the permanent tooth to erupt spontaneously. In permanent teeth or primary teeth without underlying successors, prosthetic buildup can be placed to augment the occlusal height. Severe cases in primary teeth are treated best with extraction and space maintenance. 12  Oral pathology 1 MAJD & SHATHA Lecture 8  Luxation of affected permanent teeth may be attempted with extraction forceps in an effort to break the ankylosis.  It is hoped that the subsequent inflammatory reaction results in the formation of a new fibrous ligament in the area of previous fusion.  In these cases, reevaluation in 6 months is mandatory. We have finished the study of “Environmental Alterations of Teeth”. 💪🏻 13 Oral pathology 1 MAJD & SHATHA Lecture 8 Now We will talk about “Developmental Alterations of Teeth”. DEVELOPMENTAL ALTERATIONS OF TEETH - Developmental alterations in the number of teeth - Developmental alterations in the size of teeth - Developmental alterations in the shape of teeth - Developmental alterations in the structure of teeth Number Size Shape Structure  Hypodontia  Microdontia  Gemination  Amelogenesis imperfecta (AI)  Hyperdontia  Macrodontia  Fusion  Dentinogenesis imperfecta  Concrescence (DGI)  Accessory cusps  Dentin dysplasia type I (DD-I)  Dens invaginatus  Dentin dysplasia type II (DD-II)  Ectopic enamel  Regional odontodysplasia  Taurodontism  Hypercementosis  Accessory roots  Dilaceration 14  Oral pathology 1 MAJD & SHATHA Lecture 8 DEVELOPMENTAL ALTERATIONS IN THE NUMBER OF TEETH  Variations in the number of teeth that develop are common.  Anodontia refers to a total lack of tooth development.  Hypodontia denotes the lack of development of one or more teeth.  Oligodontia (a subdivision of hypodontia) indicates the lack of development of six or more teeth excluding third molars.  Hyperdontia is the development of an increased number of teeth, and the additional teeth are termed supernumerary.  These terms pertain to teeth that failed to develop and should not be applied to teeth that developed but are impacted or have been removed.  Genetic control appears to exert a strong influence on the development of teeth.  Hypodontia and hyperdontia have been noted in patients with a variety of syndromes.  In addition, an increased prevalence of hypodontia is noted in patients with non- syndromic cleft lip (CL) or cleft palate (CP).  Genetic influences may affect non-syndromic numeric alterations of teeth, because more than 200 genes are known to play a role in odontogenesis. 15  Oral pathology 1 MAJD & SHATHA Lecture 8  The environment also has its influence, with occasional examples suggesting a multifactorial process.  Overall, hypodontia and hyperdontia most likely represent a variety of disorders caused by variable genetic and epigenetic factors.  CLINICAL FEATURES For : 1) Hypodontia  One of the most common dental developmental abnormalities, with a prevalence of 3% to 10% in permanent teeth when absence of third molars is excluded.  The prevalence increases to 20% if third molars are considered.  A female predominance of approximately 1.5 : 1 is reported.  Anodontia is rare, and most cases occur in the presence of hereditary hypohidrotic ectodermal dysplasia.  Indeed, when the number of missing teeth is high or involves the most stable teeth (i.e., maxillary central incisors or first molars), the patient should be evaluated for ectodermal dysplasia. 8-year-old male child with ectodermal dysplasia Thin, sparse hair. Short stature and low weight. Sparse light-colored eyebrows. Thin and brittle nails. Absence of all teeth. Episodes of high fever. Intolerance to heat, and lack of sweat. Light intolerance. Dry and rough skin. 16  Oral pathology 1 MAJD & SHATHA Lecture 8  Hypodontia is uncommon in the deciduous dentition with a prevalence of less than 1%.  Absence of a deciduous tooth is associated strongly with an increased prevalence of a missing successor.  Missing teeth in the permanent dentition are not rare, with third molars being the most commonly affected, followed by the second premolars and lateral incisors.  Ethnic differences have been documented.  In the deciduous dentition, 90% of missing teeth involve the maxillary lateral incisors and mandibular incisors.  Hypodontia is associated positively with microdontia, reduced alveolar development, increased freeway space, anterior malocclusion, and retained primary teeth. 17  Oral pathology 1 MAJD & SHATHA Lecture 8  TREATMENT AND PROGNOSIS  Sequelae associated with hypodontia include:  Abnormal spacing of teeth.  Delayed tooth formation.  Delayed deciduous tooth exfoliation.  Late permanent tooth eruption.  Altered dimension of the associated gnathic regions.  The management of the patient with hypodontia depends on the severity of the case.  No treatment may be required for a single missing tooth.  Prosthetic replacement often is needed when multiple teeth are absent.  In some cases, orthodontic therapy may be helpful in addition. 18  Oral pathology 1 MAJD & SHATHA Lecture 8 2) Hyperdontia  The prevalence of supernumerary permanent teeth shows ethnic variation.  The frequency of hyperdontia in the deciduous dentition is much lower than in the permanent dentition.  Most cases represent single-tooth hyperdontia, followed in frequency by two-tooth hyperdontia and three or more extra teeth in less than 1% of cases.  When all prevalence studies are combined, the most common site is the maxillary incisor region, usually single-tooth hyperdontia.  In contrast to single-tooth hyperdontia, non-syndromic multiple supernumerary teeth occur most frequently in the mandible.  These multiple supernumerary teeth occur most often in the premolar region, followed by the molar and anterior regions, respectively.  The eruption of accessory teeth is variable and dependent on the degree of space available:  75% of supernumerary teeth in the anterior maxilla fail to erupt.  Unlike hypodontia, hyperdontia is positively correlated with macrodontia and exhibits a 2:1 male predominance. 19  Oral pathology 1 MAJD & SHATHA Lecture 8  Although examples may be identified in older adults, most supernumerary teeth develop during the first two decades of life.  Several terms have been used to describe supernumerary teeth, depending on their location:  Mesiodens: a supernumerary tooth in the maxillary anterior region.  Distomolar or distodens: an accessory fourth molar.  Paramolar: a posterior supernumerary tooth situated lingually or buccally to a molar tooth. 20  Oral pathology 1 MAJD & SHATHA Lecture 8  Supernumerary teeth are divided into supplemental (normal size and shape) or rudimentary (abnormal shape and smaller size) types.  Occasionally, normal teeth may erupt into an inappropriate position (e.g., a canine present between two premolars).  This pattern of abnormal eruption is called dental transposition.  Such misplaced teeth have been confused with supernumerary teeth.  The teeth involved most frequently in transposition are the maxillary canines and first premolars.  Crowding or malocclusion of these normal teeth may dictate reshaping, orthodontics, or extraction.  Some natal and neonatal teeth may represent predeciduous supernumerary teeth, but most are prematurely erupted deciduous teeth and not supernumerary teeth (see premature eruption discussed earlier). 21  Oral pathology 1 MAJD & SHATHA Lecture 8  TREATMENT AND PROGNOSIS  The presence of supernumerary teeth should be suspected if a significant delay of normal teeth is observed in the eruption of a localized portion of the dentition.  Supernumerary teeth may develop long after eruption of the permanent dentition.  In patients previously diagnosed with supernumerary teeth, or in those genetically predisposed, long-term monitoring for additional tooth development is warranted.  Early diagnosis and treatment often are crucial in minimizing the aesthetic and functional problems of the adjacent teeth.  The standard of care is removal of the accessory tooth during the time of the early mixed dentition.  Complications created by anterior supernumerary teeth tend to be more significant than those associated with extra teeth in the posterior regions.  Spontaneous eruption of the adjacent normal dentition occurs in most cases if the supernumerary tooth is removed early.  Permanent teeth that fail to erupt are treated best by surgical exposure with orthodontic eruption. 22  Oral pathology 1 MAJD & SHATHA Lecture 8  Removal of unerupted deciduous teeth is not recommended, because most will erupt spontaneously.  Consequences of late therapy may include:  Delayed eruption.  Resorption of adjacent teeth.  Displacement of the teeth with associated crowding, dilaceration, malocclusion, diastema formation, or eruption into the nasal cavity.  Infections (pericoronitis, gingivitis, periodontitis, abscess formation).  Development of odontogenic cysts and tumors.  In selected cases, clinical judgment may not dictate surgical removal, or patient resistance to therapy may be present.  In these instances, regular monitoring is appropriate. 23  Oral pathology 1 MAJD & SHATHA Lecture 8 DEVELOPMENTAL ALTERATIONS IN THE SIZE OF TEETH  Tooth size is variable among different races and between the sexes.  The presence of unusually small teeth is termed microdontia.  The presence of teeth larger than average is termed macrodontia.  Heredity is the major factor, but both genetic and environmental influences affect the size of developing teeth.  The deciduous dentition appears to be affected more by maternal intrauterine influences; the permanent teeth seem to be more affected by environment.  CLINICAL FEATURES  Microdontia is associated strongly with hypodontia.  Macrodontia often is seen in association with hyperdontia.  Females demonstrate a higher frequency of microdontia and hypodontia.  Males have a greater prevalence of macrodontia and hyperdontia. 24  Oral pathology 1 MAJD & SHATHA Lecture 8 1) Microdontia  The term microdontia should be applied only when the teeth are physically smaller than usual.  Normal-sized teeth may appear small when widely spaced within jaws that are larger than normal.  This appearance has been historically termed relative microdontia, but in fact, it represents macrognathia.  Generalized true microdontia is uncommon but may occur as an isolated finding in:  Down syndrome,  pituitary dwarfism, and in  a small number of rare hereditary disorders  Isolated microdontia within an otherwise normal dentition is not uncommon.  The maxillary lateral incisor is affected most frequently and typically appears as a peg-shaped crown overlying a root that often is of normal length.  The alteration appears to be autosomal dominant with incomplete penetrance.  In addition, isolated microdontia often affects third molars.  Interestingly, the maxillary lateral incisors and the third molars are among the most frequent teeth to be congenitally missing. 25  Oral pathology 1 MAJD & SHATHA Lecture 8 2) Macrodontia  The term macrodontia should be applied only when teeth are physically larger than usual  The term relative macrodontia had been used for normal- sized teeth crowded within a small jaw (micrognathia).  In addition, the term macrodontia should not be used to describe teeth that have been altered by fusion or gemination.  Generalized involvement is rare, and occurs in association with:  pituitary gigantism,  pineal hyperplasia with hyperinsulinism, and  a few syndromes.  Macrodontia with unilateral premature eruption can occur in hemifacial hyperplasia.  Isolated macrodontia occurs most frequently in incisors or canines but also has been seen in second premolars and third molars.  The alteration often occurs bilaterally. 26  Oral pathology 1 MAJD & SHATHA Lecture 8  TREATMENT AND PROGNOSIS  Treatment of the dentition is not necessary unless desired for aesthetic considerations.  Maxillary peg laterals often are restored to full size by porcelain crowns. DEVELOPMENTAL ALTERATIONS IN THE SHAPE OF TEETH  Gemination, Fusion, and Concrescence  Double teeth (connate teeth, conjoined teeth) are two separate teeth exhibiting union by dentin and (perhaps) their pulps.  The union may be the result of fusion of two adjacent tooth buds or the partial splitting of one into two.  The development of isolated large or joined (i.e., double) teeth is not rare.  Historically, gemination was defined as an attempt of a single tooth bud to divide, with the resultant formation of a tooth with a bifid crown and, usually, a common root and root canal. 27  Oral pathology 1 MAJD & SHATHA Lecture 8  Conversely, fusion was considered the union of two normally separated tooth buds with the resultant formation of a joined tooth with confluence of dentin.  Finally, concrescence was the union of two teeth by cementum without confluence of the dentin.  Gemination is defined as a single enlarged tooth or joined (double) tooth in which the tooth count is normal when the anomalous tooth is counted as one.  Fusion is defined as a single enlarged tooth or joined (double) tooth in which the tooth count reveals a missing tooth when the anomalous tooth is counted as one.  Concrescence is union of two adjacent teeth by cementum alone, without confluence of the underlying dentin. 28  Oral pathology 1 MAJD & SHATHA Lecture 8  Unlike fusion and gemination, concrescence may be developmental or post-inflammatory.  When two teeth develop in close proximity, developmental union by cementum is possible.  In addition, areas of inflammatory damage to the roots of teeth are repaired by cementum once the inciting process resolves.  Concrescence of adjacent teeth may arise in initially separated teeth in which cementum deposition extends between two closely approximated roots in a previous area of damage.  Clinical Features for: 1+2) Gemination and fusion  Double teeth (gemination and fusion) occur in both primary and permanent dentitions, but frequency in deciduous teeth is greater.  In both dentitions, incisors and canines are the most commonly affected teeth.  Gemination is more common in the maxilla, whereas fusion tends to occur more frequently in the mandible.  Bilateral cases are uncommon 29  Oral pathology 1 MAJD & SHATHA Lecture 8  Gemination and fusion appear similar and may be differentiated by assessing the number of teeth in the dentition.  A variety of appearances are noted with both fusion and gemination.  A bifid crown may be seen overlying two completely separated roots, or the joined crowns may blend into one enlarged root with a single canal.  The processes may result in an otherwise anatomically correct tooth that is greatly enlarged. 3) Concrescence  Is two fully formed teeth, joined along the root surfaces by cementum.  The process is noted more frequently in the posterior and maxillary regions.  The developmental pattern often involves a second molar tooth in which its roots closely approximate the adjacent impacted third molar.  The post-inflammatory pattern frequently involves carious molars in which the apices overlie the roots of horizontally or distally angulated third molars.  This latter pattern most frequently arises in a carious tooth that exhibits large coronal tooth loss.  The resultant large pulpal exposure often permits pulpal drainage, leading to a resolution of a portion of the intrabony pathosis.  Cemental repair then occurs. 30  Oral pathology 1 MAJD & SHATHA Lecture 8  Treatment and Prognosis  The presence of double teeth (gemination or fusion) in the deciduous dentition can result in:  crowding,  abnormal spacing, and  delayed or ectopic eruption of the underlying permanent teeth.  When detected, the progression of eruption of the permanent teeth should be monitored closely by careful clinical and radiographic observation.  When appropriate, extraction may be necessary to prevent an abnormality in eruption.  Occasionally, fusion in the primary dentition is associated with absence of the underlying permanent successor.  In the permanent dentition, the treatment of choice is determined by the patient’s particular needs.  In gemination, if the double teeth have separate pulps, hemisection may be successful without root canal therapy.  In double teeth that share a common pulp, endodontic therapy is necessary if sectioning is considered.  Selected shaping with or without placement of full crowns has been used in many cases.  Extraction with prosthetic replacement is another option.  Concrescence often requires no therapy unless the union interferes with eruption; then surgical removal may be warranted. 31  Oral pathology 1 MAJD & SHATHA Lecture 8  Post-inflammatory concrescence must be kept in mind whenever extraction is planned for non-vital teeth with apices that overlie the roots of an adjacent tooth.  Significant extraction difficulties can be experienced on attempted removal of a tooth that is unexpectedly joined to its neighbor.  Surgical separation often is required to complete the procedure without loss of a significant portion of the surrounding bone. 32