Lecture 11 Flashcards
what are some options to correct dental crowding?
expand to make space, extract to make space, or interproximal reduction to make space
what are some expansion options for correcting dental crowding?
skeletal expansion and dental expansion
when planning to extract to make space as a correction for dental crowding, depending on the patients ___ and ___, orthodontists may extract a single tooth or multiple teeth
cephalometric analysis and orthodontic records
___ are the teeth most often extracted for orthodontic treatment, but any tooth (or combination of teeth) could be considered
premolars
many orthodontists under the guidance of edward angle were arguing that extraction is almost a crime. what word was used to describe this?
odontocide
what happened at the 1902 symposium on extraction at the 2nd district dental society of new york when calvin case (chief challenger of the angle’s new school) presented?
- many dentists decided never to attempt orthodontics again, but instead to refer their patients to a specialist
- this one meeting was very influential in establishing orthodontics as a separate specialty
in 1902, angle set forth his line of reasoning toward the development of his treatment philosophy. in his article, he recounts his conversations with artist edmund wuerpel, whose help led to ___
angle’s concept of facial beauty and harmony
according to angle, “my belief is that if we would confer the greatest benefits upon our patients from an aesthetic standpoint, we must work hand in hand with ___ and assist her to establish the ___ as the creator intended they should be, and not resort to mutilation”
- nature
- relations of the teeth
in angle’s “new school”, his group believed that ___ could be induced by mechanical means to grow beyond its inherent size
bone
describe the extraction debate of 1911
- calvin case presented an article entitled “the question of extraction in orthodontia”
- case claims that the causes of malocclusion partly, at least, arise from the law of heredity
- “but why enter such a field of doubt, of anger, and of possible failure, merely to satisfy a sentiment that god dose not make the mistake of placing in the mouth of the human individual more teeth than is necessary for perfect harmony in all physical and aesthetic relations?”
- why ignore the possibility and the frequent undoubted fact that inherited in-harmonies in continguous structures make it impossible for us to place all of the teeth in the arch without fulfilling the designs of an inherited deformity?
- the controversy was extensive, bitter, and irreconcilable
- angle’s contention was that there is no place for extractions in orthodontics
- case countered with what he called the “rational school” = new bone cannot be induced to grow beyond its inherent size and that, therefore, there are indications for extractions in certain forms of malocclusion
charles tweed trained under edward angle, but was familiar with case’s article “the question of extraction in orthodontia”. after 5 years of orthodontic practice, tweed became disheartened with his work for what 2 reasons?
- the protrusive faces that he was creating
- the unstable dentitions
- tweed became so disappointed that he almost left orthodontics, but resolved to study his many failures and few successes, and came to realize that patients who had pleasing facial balance and harmony also had mandibular incisors that were upright over basal bone
what was tweed’s philosophy, and how did he reach it?
- carefully planned extractions can improve appearance as well as stability
- he selected some of his treatment failures, extracted first premolars, then retreated them
- the outcomes reinforced his commitment to the necessity of extractions in certain cases
- although it was a tremendous exhibit, he was severely criticized by many orthodontists of the era
whenever there is not enough arch length in the mandibular or maxillary bases, to accommodate the size of the adult dentition, the decision must be made whether to ___ or ___
extract or expand
when adult teeth erupt, they tend to erupt with a ___ migration
mesial
if a tooth is extracted or missing, it is possible for the teeth that are located ___ to erupt ___ into the extraction/missing tooth space. this understanding popularized the concept of ___ extraction
- distally
- mesially
- serial
in 1929, kjellgren coined the term serial extraction to describe a procedure where ___
some deciduous teeth were extracted and followed by extraction of permanent teeth to guide the rest of the teeth into normal occlusion
describe what is typically completed in serial extraction cases
- first primary molar is extracted (and primary canine if necessary)
- which then encourages early eruption of the first premolar
- then the first premolar is extracted which creates space for the remaining dentition to erupt properly
during the 1940s, nance popularized the serial extraction technique in the USA and termed it ___
planned and progressive extraction
in the 1970s, holtz called the serial extraction procedure ___
active supervision of teeth by extraction
under angle, in the 1930s-1940s, when dental crowding was present, ___ was the treatment of choice
- expansion of the dental arches
- however, clinicians later found that such expansion procedures did not provide for stable results and resulted in relapse
under tweed, during the early 1940s, the wave of expansionism died out, and ___ became the treatment of choice for crowding
tooth extraction
today, trained orthodontists do a careful analysis of each problem presented by their patient and make treatment decisions based on what 5 things?
- scientific training
- clinical training
- clinical experience
- familiarity with the literature
- if necessary, consultation with peers
what are 3 things to consider with dental crowding?
- esthetics (lip support)
- stability (bony support, equilibrium of forces of soft tissues)
- gingival, bone, and tooth health
what are the contemporary extraction guidelines when the arch discrepancy is less than 4mm?
extraction is rarely indicated
what are the contemporary extraction guidelines when the arch discrepancy is 5-9mm?
extraction or non-extraction treatment is a possibility
what are the contemporary extraction guidelines when the arch discrepancy is 10mm+?
extraction is almost always requried
___ refers to a protrusive dento-alveolar position of the maxillary and mandibular dental arches that produces a convex facial profile
bi-maxillary protrusion
T or F:
some people believe that non-extraction treatment is always better than extraction treatment
true
T or F:
non-extraction treatment is thought to improve the facial profile and appearance of orthodontic patients by providing fuller lips and a broader smile
true
what are two claims of detrimental facial appearance due to extraction?
- flat lips and retracted sunken in incisors
- narrow arch widths with large buccal corridors
facial appearance is always a consideration when planning orthodontic treatment. what are 3 factors affecting it?
- genetic makeup
- environmental influences
- cultural background
how extraction vs ___ affects facial appearance is a major concern for orthodontists
arch expansion
in the study comparing smile esthetics of extraction and nonextraction patients, what was the conclusion?
- there was no difference in attractiveness between extraction and nonextraction patients
- extraction had a positive effect on the profile of patients with some combination of crowded and proclined teeth
how does proclining the mandibular incisors during treatment affect periodontal status?
- proclining the mandibular incisors more than 95* with decreased gingival thickness of less than 0.5mm increased the severity and the amount of recession
- this is a significant disadvantage for nonextraction patients with crowded mandibular incisors
for the best treatment outcomes, some patients need nonextraction treatment and some need extractions. a key goal of diagnosis is ___ on which to make this decision, rather than which ___ to use
- gathering data
- bracket
sometimes an orthodontist will order the extraction of a lower incisors, typically due to ___. this option is sometimes elected if an adult has ___
- a tooth size discrepancy
- mandibular incisor crowding with recession and bone loss on a protrusive incisor
what are 3 drawbacks to lower incisors extraction treatment?
- patient will have to be finished with a deeper bite (overbite)
- patient often will have some overjet once the case is finished
- canine guidance is sometimes difficult to achieve
___ are the most common situations where the wrong tooth is extracted
orthodontic extractions
how can orthodontics be useful prior to implant placement to replace a congenitally missing tooth?
because erupting teeth bring bone with it, orthodontic tooth movement can be used to create the alveolar bone needed to support an implant
how is root burial useful prior to implant placement?
root burial (leaving a tooth/root in place) helps maintain bone in the area until an implant can be placed
often when a patient is missing a maxillary lateral incisor, the permanent canine will drift mesially and erupt in the missing lateral position. how is this advantageous?
- due to the fact that the maxillary canine erupting in the lateral position will bring alveolar bone into the area
- once the canine has fully erupted, it can then be distalized orthodontically into its proper position, leaving a good bony site for a future implant
- or it can be left in place and lateralized to replace the missing lateral incisor
describe canine substitution for missing lateral incisors
- if the canines are an acceptable shape, minimal enameloplasty can be done to make the canine look more like a lateral incisor
- if the shape is not acceptable, the canine can be built up with composite, crowns, or veneers
canine substitution for missing lateral incisors typically has the best results when ___
both canines are used to substitute for the missing lateral incisors to help maintain smile symmetry
___ can be used to correct both the color and contour of teeth in canine substitution treatment
laminate veneers
missing lateral incisors must have the spaces maintained until implants can be placed once growth is completed. what are some space maintenance options?
- retainer to replace missing teeth
- maryland bridge
- tooth bonded to permanent retainer
- composite bridge
what are some treatment options for missing mandibular second premolars?
- close the space orthodontically (temporary anchorage device TAD)
- bridges
- implants (retention until implant can be placed)
it is common for the maxillary lateral incisors to develop small and conical in their appearance, which are referred to as ___
peg laterals
treatment options for peg laterals typically include orthodontics to ___
center the peg lateral
how can you determine how large a peg lateral should be?
- if it is present, measure the opposite side lateral incisor to determine size and shape
- if both lateral incisors are missing, the width is determined by using 2/3 the size of the central incisor as a guide
- the length should be 80% the length of the central incisor
- gingival height of the lateral should be 0.5-1mm lower than the gingival height of the central incisor and canines
if both lateral incisors are peg laterals, or if one if a peg lateral and the other is missing, what restorative problems can you foresee for these types of patients?
- size of peg lateral (build up will have to have large undercuts mesially and distally, possibly resulting in plaque traps)
- size of central incisor compared to size of implant lateral incisor (lateral incisor is typically 2/3 the width of the central incisor)
when replacing a lateral incisor, the minimum space for an implant is ___mm
7mm (3mm for the implant + 2mm on each side)
___ are the 2nd most commonly impacted or displaced tooth behind the third molars
maxillary canines
impaction of maxillary canines occurs in about ___% of the US population and is significantly more common in which gender?
- 0,8-2.4%
- females:males 2:1
what percent of maxillary canine impaction cases involve a single maxillary canine? what percent are bilaterally impacted?
- 90% single
- 8% bilateral
the majority of impacted maxillary canines are displaced toward the ___ aspect, but 20% occur toward the ___ aspect
- palatal
- facial
what are 6 reasons for maxillary canine impaction?
- crowding
- narrow maxillary arch
- a class II division II incisor relationship
- familial tendency, some patients are genetically predisposed
- follicular disturbance of the canine
- pathology to the overlying primary dentition
what are the non-orthodontic treatment options for impacted or unerupted teeth?
- if the patient is not going to undergo orthodontic treatment to correct the tooth, it is best to extract the impacted tooth to reduce the risk of future pathological or trauma to adjacent teeth
- an implant with a crown or bridge can be used to replace the missing tooth
T or F:
canines are very important for chewing and for proper occlusion, and in the vast majority of canine impaction cases, the tooth can be saved orthodontically
true
what are 3 steps to help the eruption path of the maxillary canines in a case where the canines are not overlapping the incisors but are erupting mesially, pushing on the lateral incisors root, tipping the root mesially?
- extraction of the maxillary deciduous canine
- opening space for the canine crown with routine orthodontic mechanics and/or maxillary expansion giving the canine more room and thus allowing for the spontaneous eruption of the impacted canine
- in some situations, even these techniques do not work, and the orthodontist must refer the patient to have the impacted canine uncovered surgically
how does extraction of maxillary deciduous canines facilitate the eruption of the underlying impacted permanent canine?
- it removes a possible overlying obstruction and creates a void in the bone, which activates the inflammatory response in the area
- like a corticotomy, removal of the primary tooth increases cellular differentiation and bone resorption which tends to help improve the eruption path of the maxillary canine
what are 3 problems when considering an unerupted tooth that must be surgically exposed?
- type of surgery
- how to attach to the impacted tooth
- orthodontic mechanics to bring the tooth into the dental arch
what are 3 surgical techniques for uncovering an impacted maxillary canine?
- gingivectomy
- apically positioned flap
- closed eruption technique
in an expose/bond procedure when uncovering an impacted maxillary canine, it is critical for the orthodontist that the oral surgeon bond to the ___ surface of the impacted canine, or as close to the ___ as possible
- buccal
- occlusal tip
in an expose/bond procedure when uncovering an impacted maxillary canine, what might happen if the attachment is bonded in the incorrect position?
the canine will come in sideways or backwards (worse)
in an expose/bond procedure when uncovering an impacted maxillary canine, ___ should be provided int he arch before attempting to pull the impacted tooth into position
adequate space
in an expose/bond procedure when uncovering an impacted maxillary canine, why is it important for flaps to be reflected?
so that the tooth is ultimately pulled into the arch through keratinized tissue and not through alveolar mucosa
there are multiple different types of mechanical techniques that an orthodontist uses to erupt an impacted maxillary canine, all of which depend on what 3 things?
- the tooth’s position
- occlusal relationship
- x-ray evaluation
ectopic eruption of canines (or any tooth) may cause ___ of adjacent teeth
severe root resorption
what two things are essential in preventing ectopic eruption of teeth?
early screenings and diagnosis
since resorbed incisors are mostly free of pain, ___ is essential to establish proper diagnosis
early detection via radiographic examination
why is canine angulation an important consideration in lateral incisor root resorption?
a 25% increase in the eruption angle of the canine relative to the lateral incisor increases the risk of resorption of the lateral incisor by 50%
what did Rimes and colleagues determine relative to ectopic eruption and root resorption?
the problem is often diagnosed late, both in relation to the patient’s age and to the extent of the resorption, which suggests that dental practitioners may underestimate the problem
in reference to ectopic eruption of maxillary canines and root resorption, when should you refer to an orthodontist?
as soon as you see mesial movement of the maxillary canine, and especially if the canine is disrupting the angulation of the maxillary lateral incisors, immediate referral to an orthodontist is critical
