Open bite Flashcards
(23 cards)
Open bite
Open bite
Malocclusion where space between teeth of upper and lower jaw in vertical direction
- Frequency of 1.5-5.3%, w/ average of 2-3%, and found in all types of dentitions
Open bite
Degrees of severity for open bite
- Between front teeth only
- Between front teeth and premolars
- Between all teeth=>including molars, w/ contact only between last molars (total open bite)
- Only in lateral segments=>unilateral or bilateral
- In combination w/ other malocclusions=>prognathia, progenia, and laterognathia
Open bite
Two basic forms of open bite according to etiology
- Dentoalveolar open bite=>
- Underdevelopment of front segment
- Increased mandibular angle
- Skeletal open bite=>
- Overdevelopment of lateral segments
Open bite
Main etiological factors for dentoalveolar open bite
- Thumb
- Lip
- & Tongue sucking
- Macroglossia
- Persistent infantile swallowing pattern
- Impaired nasal breathing w/ hypotonia of orbicularis oris muscle
- Impact of these habits depends on their duration, frequency, and child’s age
Open bite
Etiological factors for skeletal form of open bite
- Rachitis=>
- Poor bone formation leads to mandibular bone deformation under action of muscles=>
- Depress mandible
- Iatrogenic causes=>
- Disturbance of occlusal relationships during dental arch correction
- Expansion or preparation for Class II correction, resulting in hyperdivergent growth patterns (progenia, laterognathia)
Open bite
How tongue dysfunction and growth patterns contribute to open bites
- Vertical growth pattern=>
- Associated w/ anterior tongue dysfunction=>
- Tongue thrusts, tipping upper incisors labially and lower incisors lingually
- Horizontal growth pattern=>
- Tongue thrusts forward, causing bimaxillary dental protrusion and labial tipping of upper and lower anteriors
Open bite
Clinical findings associated with open bite
- Extraoral (frontal view)=>
- Increased lower facial height
- Lip incompetence
- Non-visible teeth when alveolar ridge underdeveloped
- Flat nasolabial folds
- Extraoral (profile view)=>
- Widening of gonial angle in skeletal form
- Intraoral=>
- Lack of contact between teeth in centric occlusion, w/ tongue positioned between teeth at rest
Open bite
Disturbances that can occur due to an open bite
- Aesthetic issues
- Impaired biting
- Speech difficulties (dyslalia)
- Mouth breathing
- Inflammation of gingiva and dental plaque build-up
Open bite
Open bite classification according to Horoshilkina
- Based on distance between incisal edges of incisors
- I degree: Up to 5 mm
- II degree: 5-9 mm
- III degree: Over 9 mm
Open bite
Methods used to analyze an open bite in study cast analysis
- Observing=>
- Size of dental arches
- Apical base
- Sagittal compensatory curve of Spee
- Occlusal relationships
Open bite
Parameters evaluated in cephalometric analysis for open bite
- Involves evaluating=>
- Facial thirds height using Nahoum index
- Growth pattern (backward rotation)
- Mandibular growth pattern using the Se-Go measurement
- Gonial angle
- Location of TMJ
- Y-axis measurements exceeding 115.5 mm
Open bite
Prophylactic measures to prevent open bite
- Eliminating etiologic factors=>
Prophylactic appliances w/ tongue guards - Myogymnastics to strengthen oral muscles
Open bite
Dentition stages of treatment for an open bite
- Primary dentition
- Mixed dentition
- Permanent dentition
Open bite
Key treatment goals when front segment infrapositioned
- Elimination of causes that restrict normal growth of alveolar ridge
- Extrusion of infrapositioned teeth
- Increasing overlap of teeth
Open bite
Prophylaxis recommended for open bites during primary and mixed dentition stages
- Eliminating=>
- Sucking habits
- Tongue thrusting
- Eruption obstacles
- Orthodontic treatment begins after 5, w/ positive motivation and rewards from parents to encourage habit changes
Open bite
Characteristics of treatment in the mixed dentition stage
- Skeletal component of AOB more pronounced
- Spontaneous correction more difficult and time-consuming
- Treatment indicated for cases that do not improve over time
Open bite
Main prohylaxis strategies for mixed dentition stage
- Habit control=> Stopping sucking habits before age 6
- Myofunctional and speech therapy=>retraining muscle activity and correcting tongue posture.
- Mastication exercises=>patients w/ neuromuscular deficiencies
- Management of airway problems and mouth breathing=>referring to specialist and using respiratory physiotherapy to restore nasal breathing
- Speech therapy=>retrain tongue and oral musculature during swallowing and speech
Open bite
Treatment options where AOB persists after 5 despite eliminating bad habits
- Fixed or removable tongue spurs or palatal cribs
- Speech therapy
- Maxillary plate w/ tongue barrier
- Mandibular plate w/ tongue barrier
- Half oral screen w/ tongue barrier according to Kraus
- Prefabricated interceptive appliances=>T4K trainers
Open bite
Treatment approaches recommended for skeletal open bites in growing patients
- High-pull extraoral appliances or vertical pull w/ chin cups=>
- Reduce or redirect vertical skeletal growth
- Intrusion of distal teeth w/ “springy” activator or surgical correction=>
- Non-growing patients
Open bite
Treatment options for skeletal open bites
- Vertical holding appliance (TPA w/ acrylic pad) to induce intrusion of upper M1
- Posterior bite blocks, activators, or modified bionators w/ headgear (HG) tubes
- High pull HG combined w/ mandibular splint covering posterior teeth
- Activator and high pull HG combinations
- Vertical chin cup w/ removable or fixed appliances
Open bite
Line of action for orthodontic force in treating skeletal open bites
- Should pass below center of resistance of both Mandibular and maxillary dentition
Open bite
General treatment protocol for skeletal open bites
- Stage 1: Preparation of dental arches, often through expansion
- Stage 2: Orthodontic treatment
- Stage 3: Surgical-orthodontic treatment if necessary
Open bite
Types of orthodontic-surgical treatment used for skeletal open bites
- Extraction of premolars in one or both jaws
- Extraction of a lower incisor
- Orthodontic-surgical treatment w/ two stages=>
- Stage I: Preparation of dental arches
- Stage II: Surgical correction of the relationship
