Prevention of Occlusal Abnormalities PDF

PREVENTION OF OCCLUSAL ABNORMALITIES By: Dr Nour Wahba Lecturer of Pediatric Dentistry Faculty of Dentistry Ain Shams University Future University...

PREVENTION OF OCCLUSAL ABNORMALITIES By: Dr Nour Wahba Lecturer of Pediatric Dentistry Faculty of Dentistry Ain Shams University Future University 2024-2025 ILOs: By the end of this chapter, every student should be able to: 1. Differentiate between preventive, interceptive, and comprehensive orthodontics. 2. Understand etiological factors causing different malocclusion conditions. 3. Identify different malocclusion conditions that occur in the primary and mixed dentition. 4. Recognize cases that require early interventions. 5. Apply preventive and interceptive treatment modalities for different malocclusion conditions. 1 Definitions: I. Preventive Orthodontics: Primary prevention of malocclusion before its occurrence. It deals with primary dentition. - Preventive Procedures include: → Oral Health Promotion: 1. Parent Counselling/ Education: Anticipatory Guidance; - pre- and postnatal counselling regarding oral hygiene measures for children, proper feeding habits, prevention of oral habits. 2. Environmental support for actions and conditions and living conditions thatare conducive to oral health. → Specific Protection: 1. Care of deciduous teeth: - Regular dental check-ups. - Caries Control - Space Maintenance - Management of oral habits - Management of high frenal attachment - Management of supernumerary teeth - Management of ectopic eruption 2  II. Interceptive Orthodontics: - The early diagnosis and prompt treatment of unfavorable features of a developing occlusion that may make the difference between achieving a satisfactory result by simple mechanics later, thus reducing overall treatment time and esthetic results. - Secondary level of prevention of a malocclusion after its occurrence. - Deals with mixed dentition - It is the early treatment of the developing malocclusion to prevent the full expression of the malocclusion and hence facilitate easier and less treatment. - Interceptive Orthodontics include: - All procedures of preventive orthodontics and additionally: 1. Space Regainers 2. Management of Oral habits 3. Management of cross bites 4. Management of midline diastema 5. Orthopedic Guidance of Eruption 6. Management of canine impactions 7. Management of Ectopic Eruption 3  III. Comprehensive Orthodontics: - 3ry level of prevention of malocclusion after its occurrence and complications. It aims at limiting the disability caused by the malocclusion and the rehabilitation of the occlusion. - Comprehensive Orthodontics procedures: 1. Fixed orthodontic appliances (braces) Normal Development of Occlusion: 1. Primary Dentition: The three features of primary dentition that indicate good dental 2. development are: - Spaces: generalized interdental spaces, primate spaces (mesial to upper canine and distal to lower canine, they help in the placement of the canine cusp in the opposing arch) - Types of occlusion: flush terminal plane, mesial shift at 3-6 years. 3. Mixed Dentition: → 3 important events occur: I. Eruption of first permanent molar (FPM): a. Mesial Step: allows the development of Angle Class I occlusion b. Flush Terminal Plane 4 II. Eruption of incisors (insical liability): -The difference in amount of space occupied by primary anteriors and the space needed for the eruption of permanent anteriors is called incisal liability, which is 7mm in upper arch and 5mm in the lower arch. This is compensated by three main mechanisms: a. Increase intercanine width b. Closure of the generalized and primate spaces. c. Proclination of upper permanent incisors leading to increased arch length / Perimeter. III. Ugly duckling stage/ Boradbent Stage 4. Permanent Dentition: - Angle Class I, II, III 5  Etiology of Malocclusion: 1. Skeletal Factors: - The relationship between the mandible and maxilla in the Anteroposterior, Transverse and Vertical Dimension (relation of overjet and overbite, and occlusion of teeth in the buccal segment). - Two aspects in skeletal factors are important: size and position of Mandible/ Maxilla. - Maxilla is the leader in growth and mandible follows it. 2. Soft Tissue form and function: - Dental arches and skeletal pattern develop in a soft tissue environment. - Muscular activity of lip s, cheeks, tongue and muscles of mastication have a profound effect on the occlusion of teeth. - They affect the labiolingual inclination of teeth and the development of buccal segment crossbites. 6 3. Oral Habits: - Affect the occlusion of teeth - Most important factors are duration, frequency and intensity. - Their effect is very variable because they mainly cause dento-alveolar changes which affects the angulation of teeth not the underlying skeletal pattern. Preventive and Interceptive Measures: A. Primary Level of Prevention of Malocclusion (before the occurrence of the malocclusion): 1. Oral Health Promotion: Parenting Counselling and Education: → Oral health education to expecting mothers, anticipatory guidance and regular dental check-ups provide the necessary knowledge for parents regarding their children’s future dental health including growth and development, importance of preserving the primary dentition, prevention of traumatic injuries, proper feeding habits, prevention of non- nutritive sucking habits, etc. This helps parents identify any abnormality early enough and therefore seek proper treatment. In addition to the environmental support for actions and conditions that are conducive to health. 2. Specific Protection: Caries Control: o Since deciduous teeth serve as ‘Natural Space Maintainers’ for their successors, effort must be done to preserve them in a good condition. o Studies showed that interproximal caries (Class II cavities) in deciduous dentition increases the risk of decrease of arch length, which may increase the risk of crowding in the permanent dentition. 7  Space Maintainers (SM): o The primary dentition guides the eruption of the permanent teeth. They are considered the ‘Best/ Natural Space Maintainers’. - Premature loss of a primary tooth → undesirable adjacent teeth movement → loss of space for permanent dentition → the need for orthodontic treatment. o Consequences of early loss of primary teeth: loss of space for the permanent successor, crowding, impaction, ectopic eruption, midline shift, over-eruption of opposite teeth and the need for comprehensive orthodontic treatment. o Prior to considering space maintenance, determine the patient’s oral health status (oral hygiene and caries risk assessment), since SM will allow plaque accumulation and gingival diseases, therefore the patient must be dentally fit before considering SM: - caries stabilized; - motivated to maintain proper oral hygiene; - follows a non-cariogenic diet; - regular attenders for follow up; cooperative for its placement. o Factors that help in the decision for SM: - Amount of bone covering the permanent successor; - time elapsed since the tooth loss; - tooth/ teeth lost in the arch; - presence and root development of the permanent successor; - current malocclusion; - individual arch space/length analysis. o Contra-indication for SM: lack of space for the permanent successor → the need for space regainer. 8  B. In the Mixed Dentition (Secondary Level of Prevention of Malocclusion) Retained Primary Teeth: - Definition: presence of primary teeth in the oral cavity beyond their expected exfoliation date. - Etiology: → Congenitally missing, ectopic eruption, impacted or primary failure of eruption of permanent successor. - Sequelae: Primary teeth can function well or become submerged and ankylosed in case of congenitally missing permanent successor. a. Diagnosis: using radiographs (Panoramic Radiograph) to identify the presence or absence of the successor tooth. b. Examples: 1. Retained primary canines: in case of the eruption of the permanent canines, their predecessors have to be extracted bilaterally to avoid midline shift. 2. Retained primary incisors: lingual erupted mandibular permanent incisors in the presence of retained primary incisors is a common condition that needs to be followed up until the patient is 7 years before taking the decision to extract the mandibular primary central incisors and 8years before extracting the mandibular primary lateral incisors. The tongue will help reposition the teeth in their correct position. In case of retained maxillary primary central incisors in the presence of the maxillary permanent incisors, the predecessors have to be extracted once diagnosed to prevent the occurrence of the anterior crossbite. 3. Retained first or second primary molars: diagnosing the presence of congenital absence of the 1st and 2nd premolars is important to create a treatment plan. 9  Ectopic Eruption of Permanent Teeth (First Permanent Molars): Definition: Ectopic eruption describes the eruption of a tooth into an atypical position. Most common teeth: Maxillary FPM; Maxillary canines. Etiology: multifactorial; strong genetic element; high incidence in cleft lip and palate patients. - local factors as mesial angulation of FPM, larger than average width of FPM, crowding, unfavorable shape of the second primary molar. Classification of ectopic erupted FPM: 10  - Reversible vs. Irreversible: permanent molar spontaneously self corrects before 7 years and erupts in a normal position (reversible) or permanent molar remains blocked by the primary molar (irreversible). Diagnosis: clinically by observing a locked FPM behind the second primary molar. Radiographs confirm the diagnosis by showing a mesially tilted FPM associated with the distobuccal root of the primary second molar. Consequences: pain and infection related to the second primary molar; premature exfoliation of the 2nd primary molar; mesial migration of the FPM occupies the space of the 2nd primary molar which decreases the arch perimeter and may impinge on the eruption or impaction of the second premolar. - Management: There are 4 factors that affect the management of ectopic erupted FPM: 1. Age: reversible ectopic eruption occurs before 7 years. If diagnosed before 8 years, a six month observation is a must thereafter active treatment is indicated. 2. Status of the second primary molar: If pain of irreversible pulpitis or mobility exists then extraction and space maintenance. 11 3. Presence/ Absence of the second premolar: congenital missing 2nd premolar indicates extraction of the 2nd primary molar and allow the FPM to close the space. 4. Severity of impaction: Grade 1 can be observed for spontaneous correction. Grade 2 requires interproximal wedging or distal tipping. Grade 3 active distal tipping. Grade 4 extraction of the primary second molar. - Separation techniques: I. Interproximal wedging: A separating medium is placed between the FPM and the primary second molar. Caution against apical dislodgment of the separator. a. Elastomeric Separator: used when little movement is required and followed up every two weeks. b. Brass wire: used when small amount of movement is needed; an 0.5mm wire is threaded around the contact point between both molars then twisted to tighten the wire. Disadvantage: painful procedure requires local anesthesia. c. Other option: separation using orthodontic band. II. Distal Tipping: a. Transpalatal arch (TPA) with distal hook: TPA on the primary molar with cantilever arm extending distally. An elastomeric band or spring can then be hooked from the end of the 12 cantilever arm to a button which has been bonded on to the permanent molar to initiate distal movement of the ectopic molar. b. Fixed Orthodontic Appliance – Relapse: To prevent relapse of FPM, place a band on the second primary molar with a distal extension on the occlusal surface and follow up the patient every 6-8 weeks. The band stays in place until the full eruption of the FPM. i. Space Regaining: If the second primary molar was lost or extracted: An active TPA for de-rotation of the FPM or Nance appliance can be used. 13  Management of Unerupted Permanent Incisors: - Normal eruption date: 7-9 years Most commonly affects the maxillary rather than the mandibular incisors. - Etiology: → Hereditary: Supernumerary teeth, cleft lip and palate, odontomes, abnormal tooth/tissue ratio, generalized retarded eruption, gingival fibromatosis. → Environmental: Trauma to the predecessor causing dilaceration of permanent incisor, early extraction or loss of deciduous teeth (with or without space loss), retained deciduous teeth, cysts, endocrine abnormalities, bone disease. - Diagnosis: → Dental and medical history: should be obtained to determine possible hereditary or environmental factors, which may be contributory to the delay in eruption. → Delayed eruption of a maxillary incisor is considered when: the contralateral tooth has erupted for more than six months, when the opposing centrals had erupted for one year or when there is significant deviation from the normal eruption sequence (lateral incisors erupting before the central incisor). Examination: to identify the presence of deciduous teeth retained beyond their normal exfoliation dates. Buccal or palatal swellings should be noted as well as the availability of suitable space for the eruption of the incisors. Radiographic Examination: Periapical, panoramic Radiograph, anterior occlusal or CBCT are suitable for the exact localization of the unerupted maxillary permanent incisor. 14 Management Principles: Aim: allow for normal eruption to preserve the gingival attachment and prevent gingival recession that is accompanied by orthodontic traction. 1. Physical Obstruction: Remove retained primary tooth or any physical obstruction: if there is not more obvious cause or if the permanent incisor is close to eruption. Remove any physical obstruction: such as supernumerary teeth or odontomes. 2. Space: Create and maintain sufficient mesial and distal space. 3. Follow up for 18 months to allow for spontaneous eruption which will allow for normal gingival margin and will prevent any gingival recession liable to happen in case of orthodontic exposure. 4. >18 months: Exposure of the incisor will be required. 15  Management of Midline Diastema: - Causes: - Supernumerary teeth in the midline (mesiodens); - Familial pattern; midline intrabony pathological processes; - small teeth; protruding incisors; - physiological in the ugly duckling stage; - High labial frenum. - Management depends on the cause of the midline diastema. Diastemas due to: → Supernumerary Teeth: extraction and space usually close alone. → Rotated, flared anteriors or diastema due to familial pattern are treated with fixed or removable orthodontic appliances. → Small upper anteriors relatively to lower anteriors: addition of resin to the interproximal surfaces of maxillary incisors. → High frenal attachment: orthodontic closure first and then surgical removal of the labial frenum to allow the scar tissue to heal on the new tooth position. → Ugly duckling stage: will resolve spontaneously after eruption of the permanent canines. - Retention of the closed diastema is essential regardless of its cause. 16 Dentists’ Role in the management of malocclusions: During the regular examinations of the child, the dentist should be able to: 1.Understand normal dentofacial growth and development and the interrelation between jaws and teeth, including: → 3-6 years: interdental spacing. → 6-8 years: crowding of permanent incisors anterior crossbite, open-bite, and ectopic eruption of 6. → 8-10 years: space available for unerupted 3,4,5 position of maxillary canines. → 10-12 years: eruption of canines and premolars. 2. Recognize early deviation from normal, for example, delayed eruption of permanent maxillary incisors due to the presence of supernumerary teeth. 3. Understand the various etiological factors in malocclusion. 4.Record the possible harmful habits such as thumb sucking tongue thrusting, lip habits, incorrect swallowing patterns etc. As some of the deformities will correct themselves if the child stops the habit. 5.Recognize the cases need early intervention, for example, extraction of retained primary incisors to prevent palatal or lingual eruption of the permanent incisors. 6.Recognize when it is better to wait and delay orthodontic treatment and when consult an orthodontist. 17