Ortho, G+D, CF Flashcards
What three major categories do diagnostic orthodontic evaluations fall under?
- Health of the teeth and oral structures
- Alignment and occlusal relationships of the teeth
- Facial + jaw proportions
General considerations + principles of management
- Primary dentition: Beginning in infancy with the eruption of the first tooth, usually ~6mo, and complete from ~3-6yo when all primary teeth are erupted
- Mixed dentition: 6-13yo, primary + permanent teeth present in the mouth.
- Early mixed
- Late mixed
- Adolescent dentition: All succedaneous teeth have erupted, second permanent molars may be erupted/erupting, third molars have not erupted yet.
- Adult dentition: All permanent teeth present.
Objectives of dental development evaluation include identification of:
- All tooth number + size anomalies
- Anterior + posterior crossbites
- Presence of habits along with their dental + skeletal sequelae
- Open bite
- Airway problems
What should you look out for in late mixed dentition, dental development-wise?
Ectopic tooth positions (canines, premolars, and second permanent molars)
What should you look out for in adolescent dentition, dental development-wise?
Ortho diagnosis and treatment should be planned for Class I crowded, Class II, and Class III malocclusions as well as posterior and anterior crossbites. Third molars should be monitored as to position and space.
What should you look out for in adult dentition, dental development-wise?
Evaluate third molars
When should habits and crossbites be addressed?
If predicted not likely to be self-correcting, they should be addressed as early as feasible to facilitate normal occlusal relationships
Early mixed dentition treatment considerations
- Habits
- Arch length shortage
- Intervention for crowded incisors
- Intervention for ectopic teeth
- Holding of leeway space
- Crossbites
- Openbite
- Surgical needs
- Adverse skeletal growth
Late mixed dentition treatment considerations
Skeletal disharmonies + crowding
Adolescent dentition treatment considerations
Orthodontic diagnosis and treatment can provide the most functional, stable, and esthetic occlusion
What is the relationship between oral habits + unfavorable dental and facial development?
- Associational.
- Oral habits may apply negative forces to the teeth + dentoalveolar structures
- Duration of force is more important than its magnitude
- The resting pressure from the lips, cheeks, and tongue has the greatest impact on the tooth position as these forces are maintained most of the time.
Oral habits
- Non-nutritive sucking
- Bruxing
- Tongue thrust swallow
- Abnormal tongue position
- OSAS
What type of malocclusion is commonly associated with long-term non-nutritive sucking?
Anterior openbite + posterior crossbite
When should sucking habits be discontinued?
36mo or younger
Complications of bruxism?
Dental attrition, headaches, TMD and soreness of masticatory muscles
Juvenile bruxism is self-limiting and does not persist in adults.
Tongue thrusting
- Abnormal tongue position + deviation from the normal swallowing pattern
- May be associated with anterior open bite, abnormal speech, and anterior protrusion of the maxillary incisors
When is a tongue thrust considered clinically significant?
If the resting tongue posture is forward of the normal position, incisor displacement is likely. If resting tongue posture is normal, a tongue thrust swallow has no clinical significance.
In what population does self-injurious or self-mutilating behavior occur?
Special needs populations – associated w/ developmental delay or disabilities, psychiatric disorders, traumatic brain injuries, and some syndromes
MOST NOTABLY LESCH-NYHAN SYNDROME
Treatment options for self-injurious behavior
- Pharmacologic management
- Behavior modification
- Physical restraint
- Lip bump
- Occlusal bite appliances
- Protective padding
- Extractions
Treatment options for severe lip- and tongue-biting habits
- Monitoring
- Odontoplasty
- Bite-opening appliance
- Extraction
Severe lip- and tongue-biting habits may be associated with profound neurodisability due to severe brain damage.
Clinical presentation of OSAS
- Narrow maxilla
- Crossbite
- Low tongue position
- Vertical growth
- Increased OJ + OB
- H/o snoring, apnea, restless sleep, daytime neurobehavioral abnormalities or sleepiness, bedwetting.
- Growth abnormalities, signs of nasal obstruction, adenoidal facies, enlarged tonsils.
Hypodontia (permanent teeth) – Prevalence
Reference Manual
3.5-6.5%
What is the most frequently missing permanent tooth?
Excluding thirds, mandibular second premolar, followed by the maxillary lateral incisor.
Hypodontia (primary teeth) – Prevalence
Reference Manual
Less frequent than permanent teeth.
0.1-0.9%
Almost always affects the maxillary incisors + 1st primary molars
What other dental features are seen in patients w/ congenitally missing teeth?
- Asymmetric eruption sequence
- Over-retained primary teeth
- Ankylosis of primary mandibular second molar
Supernumerary teeth – Prevalence
- 5x more common in the permanent dentition but do occur in primary teeth.
- Primary: 0.3-0.8%
- Mixed dentition: 0.52-2%
- Early mixed: 79-91% of anterior permanent supernumerary teeth are unerupted.
- 80-90% in the maxilla, w/ ½ in the anterior and almost all palatally positioned.
- Supernumerary primary followed by a supernumerary permanent tooth in ⅓ of cases.
Percent of mesiodens eruption with age
25%
Effect of mesiodens on adjacent teeth
- Can prevent or cause ectopic eruption of central incisor
- Cause dilaceration or resorption of permanent incisor’s root (less frequent)
- Dentigerous cyst formation
Imaging that can determine supernumerary’s position
Pano, occlusal, PA can reveal supernumerary’s presence.
- Determine position:
- CBCT
- 2 PAs/occlusals reviewed by the parallax rule
Timing for extraction of mesiodens
- Early mixed dentition (6-7yo, permanent root length
- Later removal reduces likelihood that the adjacent normal permanent incisor will erupt on its own, especially if the apex is completed
- Inverted conical supernumerary teeth can be harder to remove if removal is delayed, as they can migrate depper into the jaw.
Supernumerary tooth extraction follow up
Clinical + radiographic follow up 6m post-op to determine if the normal incisor is erupting. If there is no eruption after 6-12m, and there is sufficient space, sx exposure + orthodontic extrusion may be needed.
When can ectopic eruption of permanent molars be dx’d?
From BWX or pano in early mixed dentition
What type of crowding is ectopic eruption of first permanent molars associated with?
Transverse + sagittal
More common in the maxillary arch + CLP
Likelihood of self-correction of ectopically erupting permanent molars
66% self-correct by 7yo
71% self-correct by 9yo
What factors indicate a need for early intervention with ectopically erupting permanent molars?
- Increased magnitude of impaction
- Increased resorption of the primary tooth
- Bilateral occurrence
Impacted maxillary canine %
1.5-2% of the population
When should you suspect impacted U3s?
Canine bulge is not palpable, asymmetric canine eruption, peg=shaped lateral incisors
When should you expect ectopic eruption of permanent incisors?
- After trauma to primary incisors
- Pulpally treated primary incisors
- Asymmetric eruption
- Supernumerary incisor
Ectopic eruption of 1st permanent molars – Treatment
Determined by severity.
- Mild – Little of the tooth is impacted under the primary second molar
- Elastic or metal orthodontic separators can be placed to wedge the permanent first molar distally.
- Severe – Distal tipping of 1st permanent molar is required.
- Brass wires, removal appliances w/ springs, fixed appliances such as sectional wires w/ open coil springs, sling shot-type appliances, Halterman appliances
Ectopic eruption of U3s – Treatment
- Depends on etiology
- Extraction of Uc’s (when canine bulge cannot be palpated + radiographic overlap with lateral during mixed dentition)
- RPE + cervical pull headgear in mixed dentition.
- EXT of Ud’s has been reported to allow eruption of U4s and to assist in eruption of U3s
Uc extraction when impacted U3 diagnosed at a later age (11-16yo)
If the canine is not horizontal, EXT of Uc lessens the severity of the permanent canine impaction and 75% will erupt
Process of ankylosis
Cementum of tooth root fuses directly to surrounding bone. PDL is replaced w/ osseous tissue, rendering the tooth immobile.
Can occur rapidly or gradually; may be transient, where only a small bony bridge forms and then is resorbed by osteoclastic activity
Ankylosis – Incidence
- Primary: 7-14%
- Permanent: Occurs most frequently following luxation injuries
Ankylosis – Management
- Maintain until interference w/ eruption or tipping/drifting of adjacent teeth, and when that does occur → EXT and place LHA or fixed appliance if needed.
Ankylosed primary molars w/o permanent successor – Management
- If severe infraocclusion → EXT before a large vertical occlusal discrepancy develops or decoronation to maintain alveolar width and prevent further loss of vertical height.
What is an alternative to premature extraction of ankylosed permanent teeth?
Surgical luxation with forced orthodontic eruption.
Permanent incisor decoronation
- RCT
- Removal of clinical crown + cervical portion of the root to a level at least 2mm below marginal bone height, followed by reflecting, repositioning, and suturing a mucoperiosteal flap over the root.
Primary failure of eruption
An eruption disorder characterized by partial or complete non-eruption of permanent teeth in the absence of any mechanical obstruction or syndrome.
What teeth are most commonly affected by primary failure of eruption?
Posterior teeth; one or all four quadrants may be involved
Two main phenotypes of primary failure of eruption
- All teeth distal to the most mesial non-erupted tooth are affected
- Unerupted teeth do not follow the pattern that all teeth distal to the most mesial involved are also affected
Hallmark features of primary failure of eruption
- Posterior open bite in the presence of normal vertical growth
- Infra-occlusion of affected teeth
- Inability to move affected teeth orthodontically
Primary failure of eruption vs. ankylosis
PFE: Eruption fails to occur due to an imbalance in resorptive + appositional factors related to tooth eruption.
Teeth w/ PFE are not initially ankylosed but may become ankylosed when orthodontic forces are applied.
Primary failure of eruption etiology
- 85% of patients w/ PFE have another family member w/ the condition.
- Variable expression and has been associated w/ mutations in the autosomal dominant parathyroid hormone receptor gene (PTH1R)
Contraindications w/ patients that have primary failure of eruption
Early orthodontic intervention of the affected teeth. There are no established mechanotherapeutic methods of modifying dentoalveolar growth for these patients
Primary failure of eruption treatment objectives
Reassurance + education about the eruption disorder and preparation for future prosthetic rehabilitation.
Early extraction can improve normal development of the alveolus and permanent dentition in some cases.
When can you suspect ectopic eruption of permanent first molars?
- Asymmetric eruption
- Mesial marginal ridge is under the distal prominence of the second primary molar
Percentage of ectopic permanent molars that self-correct?
66% self-correct by age 7
71% correct by age 9
Treatment considerations: Mildly impacted permanent molars
Elastic or metal ortho separators can help wedge permanent first molars distally
Treatment considerations: Severely ectopic permanent molars
Distal tipping of permanent molar is required by tipping w/ brass wires, removable appliances using springs, fixed appliances such as sectional wires w/ open coil springs, sling-shot appliances or Halterman appliance
When can you clinically suspect impacted U3s?
- Canine bulge is not palpable
- Asymmetric canine eruption
- Peg-shaped lateral incisors
When can you radiographically suspect impacted U3s?
- Pan may show if canine has abnormal inclination
- If canine crosses the lateral root long axis midline, it will self-correct only 64% of the time; if it does not, it has a 91% chance of self-correcting.
- Enlarged follicular sac
- Lack of root resorption of primary canines
- Presence of premolar impaction
If canine crosses the lateral root long axis midline, what percent of the time will it self-correct?
If canine crosses the lateral root long axis midline, it will self-correct only 64% of the time; if it does not, it has a 91% chance of self-correcting.
Bolton discrepancy
Arch length discrepancies, include inadequate arch length + crowding of the dental arches, excess arch length + spacing, tooth size discrepancy.
May be found w/ complicating + other etiological factors: missing teeth, supernumerary teeth, fused or geminated teeth
When do transseptal fibers develop?
Not until the CEJ of erupting teeth pass the bony border of the alveolar process
When should initial assessment of tooth size/arch length discrepancy and crowding be done?
Early mixed dentition, when mandibular incisors begin to erupt.
The loss of what tooth in the mouth is the most detrimental?
Primary second molar
When do the biggest changes happen in space loss following extraction?
4-8 weeks after extraction
Fixed space regaining appliances
- Holding arch
- Pendulum appliances
- Halterman-type appliances
- Jones jig
Removable space regaining appliances
- Hawley w/ springs
- Lip bumper
- Headgear
Unilateral crossbites are a manifestation of what most often?
Bilateral crossbite w/ a functional mandibular shift
When should functional shifts be addressed?
Should be eliminated ASAP w/ early correction to avoid TMD and/or asymmetric growth
When is skeletal expansion w/ fixed or removal palatal expanders no longer an option?
When the midline suture fuses [11-13yo girls, 14-16yo boys]
What is a OJ >3mm associated with?
Increased risk of incisor injury.
Large (>8mm) resulting in trauma >40% of children
