Spring - Final Flashcards
What are the three main treatment options for phase I maxillary crowding?
- Expansion
- Limited orthodontics on maxillary first molars and incisors
- Extraction of primary canines (or others as needed) to create space for erupting permanent teeth
This test is crazy!
What are the major reasons to do early maxillary expansion in the mixed dentition?
- To eliminate mandibular shifts on closure
- To provide more space for the erupting maxillary teeth
- To lessen dental arch distortion and potential tooth abrasion from interferences of anterior teeth
- Reduce the possibility of mandibular skeletal asymmetry
What are the characteristics of indentations in the superior surface of the tongue?
W-arches, quad helixes, expanders, and habit appliances can leaven indentations on the tongue, and they often remain after appliance removal for up to 1 year. No treatment is recommended but parents and patients should be aware.
What are the possible treatment options for phase I mandibular crowding?
- Expansion (only dental expansion, not skeletal) with a schwartz, or lip bumper
- Limited ortho on mandibular permanent teeth
- Extraction of primary canines (or others as needed) to create space for erupting permanent teeth
What are the characteristics of treating class III skeletal growth patterns in phase I ortho treatment.
– The early you get started with these patients, the better.
– Patients are typically in an anterior crossbite with maxillary constriction and can be in full posterior cross bite
– Class III growth patterns are very difficult to control, especially in males, and referral to an orthodontist should be initiated as soon as possible
– Treatment for these patients typically consists of limited orthodontic treatment on the permanent dentition in association with expansion and reverse pull head gear.
– If forward traction is applied at an early age, it is possible to produce forward displacement of the maxilla rather than just displacement of maxillary teeth
What are the characteristics of treating class II skeletal growth patterns in phase I ortho treatment?
-- Unless they have another problem that can be treated in phase I, like mandibular crowding, just wait to do one full treatment later on instead of in two phases if they have class II skeletal growth. • Unlike early treatment for a skeletal class III patient, phase I treatment for a skeletal class II patient is not as common. • A lot of research has been done comparing children who have undergone phase 1 growth modification for class II skeletal growth, and the following has been concluded about the early attempts and the benefits of early treatment for class II problems. – Skeletal changes are likely to be produced by early treatment with head gear or a functional appliance but tend to be diminished or eliminated by subsequent growth and later treatment -- Skeletal changes account for only a portion of the treatment effect, even when an effort is made to minimize tooth movement – After later comprehensive treatment, alignment and occlusio are very similar in children who did and those that did not have early treatment – Early treatment does not reduce the number of children who require extractions during a second phase of treatment or the number who eventually require orthognathic surgery – The duration of phase II treatment (full ortho treatment) is quite similar in those who had a first phase of early treatment aimed at growth modification and those that did not • Based on these results, it seems clear that for most class II children, early treatment is no more effective than just one phase of later treatment
What are the characteristics of permanent first molars erupting ectopically?
• Moderately advanced resorption of the primary second molar, from ectopic eruption of the permanent maxillary first molar requires active intervention.
• In these x-rays the distal root of the primary maxillary second molar shows enough resorption that self- correction is highly unlikely.
• Sometimes a spacer can be placed between the teeth to distalize the first molar other times active orthodontic treatment must be performed to distalize the tooth
• Due to the resorption of the distal root of the primary tooth, it is often necessary to extract the primary second molar.
– Space maintenance should be incorporated into the treatment plan.
The permanent incisor tooth buds are positioned buccally to the primary incisors. True or False?
False, lingually
Lingual arches should not be placed until after the lower incisors erupt. True or False?
True, because of the ectopic eruption that can happen lingually and tooth buds that are found lingually
What is tooth fusion?
• Tooth Fusion is when two tooth buds fuse together to make one large wide crown. The fused tooth will have two independent pulp chambers and root canals. The fusion will start at the top of the crown and travel possibly to the apex of the root. So you are missing one tooth when you count all the teeth.
What is tooth gemination?
• Tooth Gemination is when one tooth bud tries to divide into two teeth. The tooth count is normal with gemination. On a radiograph, the geminated tooth will have one pulp canal but two pulp chambers.
Treatment options for fused or gemination teeth are usually not good. True or False?
True. The teeth typically are extracted but sometimes can have RCT and then the crowns can be re-contoured.
– Restore fused tooth with RCT
– Extraction with implant replacement
– Autotransplantation
– Orthodontic space closure and substitution
Early loss of a primary tooth presents a potential alignment problem because drift of permanent or other primary teeth is very likely unless it is prevented. True or False?
True
Space maintenance is always appropriate. True or False?
False. Only when adequate space is available, and when all unerupted teeth are normal and at the normal stage of development. If there is not enough space for the permanent tooth or if the permanent tooth is missing, space maintenance alone is inadequate or inappropriate and other treatment approaches are necessary. If a space maintainer is used it must be monitored carefully for breakage and leakage to be successful.
If a permanent successor will erupt within 6 months (ie: there is more than one-half to two-thirds of its root formed), a space maintainer is unnecessary. True or False?
True
What are the characteristics of a band and loop space maintainer?
– Band and loop–Because the loop has limited strength, this appliance must be restricted to holding the space of one tooth and is not intended to accept the functional forces of chewing
• Should you solder a loop to a stainless steel crown? No, ideally no.
• Should you band the primary or permanent tooth?
– Risk of decay to permanent tooth
– Evaluate x-ray to evaluate when the
primary tooth will be lost
• If a single primary molar has been lost bilaterally, a pair of band and loop space maintainers is recommended instead of the lingual arch that would be used if the patient were older because the primary incisors often erupt lingually, which would interferer with their eruption.
• Band and loop survival is not impressive and has been judged to be about 18 months with cement failure being the most frequent problem
What are the characteristics of distal shoe space maintainers?
– Distal Shoe
- The distal-shoe space maintainer is indicated when a primary second molar is lost before eruption of the permanent first molar and is usually placed at or very soon after the extraction of the primary molar.
- The loop portion, made of 36 mil stainless steel wire, and the intra-alveolar blade are soldered to a band so the whole appliance can be removed and replaced with another space maintainer after the permanent molar erupts
- The loop portion must be contoured closely to the ridge since the appliance cannot resist excessive occlusal forces from the opposing teeth.
- The blade portion must be positioned so that it extends approximately 1 mm below the mesial marginal ridge of the erupting permanent tooth to guide its eruption. This position can be measured from pretreatment radiographs and verified by a radiograph taken at try-in or post- cementation.
- An additional occlusal radiograph can be obtained if the faciolingual position is in doubt.
What are the characteristics of lingual arch space maintainers?
– Lingual arch - A lingual holding arch usually is the best choice to maintain space for premolars after premature loss of the primary molars when the permanent incisors have erupted.
– The lingual arch is stepped away from the premolars to allow their eruption without interference, which results in a keyhole design. The wire is also 1.5 mm away from the soft tissue at all points.
– A lingual arch on the maxillary teeth can be used if the overbite is not excessive
– A spur on a lingual arch can be used in the mixed dentition either to maintain a correct midline when a primary canine is lost or to retain a corrected midline.
What are the characteristics of a nance space maintainer? When is it indicated?
- Nance - a Nance arch with an acrylic button in the palatal vault is indicated if the overbite is excessive. The palatal button must be monitored because it may cause soft tissue irritation.
What are the characteristics of a transpalatal arch space maintainer?
Transpalatal arch - The transpalatal arch prevents a molar from rotating mesially into a primary molar extraction space, and this largely prevents its mesial migration. Several teeth should be present on at least one side of the arch when a transpalatal design is employed as a sole space maintainer.
What are the characteristics of removable space maintainers?
– Removable retainers • Removable hawley (wire labial bow) retainer with tooth • Removable essix with tooth • Removable partial denture - In a young child, a removable partial denture is used to replace anterior teeth for esthetics. At the same time, it can maintain the space of one or more prematurely lost primary molars. For this patient, the four incisors are replaced by the partial denture. Multiple clasps, preferably Adams’ clasps, are necessary for good retention. Both the clasps and the acrylic need frequent adjustment to prevent interference with physiologic adjustment of primary teeth during eruption of permanent teeth
Premolars are the teeth most often extracted due to ortho treatment, but any tooth, or combination, could be used. True or False?
True
What did Edward Angle believe?
Extraction for ortho treatment is almost a crime, called people that did it odontocides. Taught that bone could be induced by mechanical means to grow beyond its inherent size. Calvin Case taught the opposite, and that there are indications for extractions in certain forms of malocclusion.
What is Charles Tweed’s story?
Tweed trained under Angle, but had also read Case’s articles, and was bugged by his bad cases where he didn’t extract any teeth. He re-did some and found that extractions can be beneficial. This was in the 1950’s.
What are the things to consider in patients with severe dental crowding?
- Esthetic considerations (lip support)
- Stability considerations (bony support, equilibrium of forces of soft tissues)
- Gingival, bone and tooth health
What are the mm rules for arch length discrepancy and extraction requirement?
- Arch length discrepancy of less than 4 mm = extraction is rarely indicated
- Arch length discrepancy of 5 mm to 9 mm = extraction or non-extraction treatment is a possibility
- Arch length discrepancy of 10 mm or more = extraction is almost always required
What is bi-maxillary protrusion?
• Bi-maxillary protrusion refers to a protrusive dento- alveolar position of the maxillary and mandibular dental arches that produces a convex facial profile.
- Patients with this can have all four first premolars extracted to retract the protrusive incisors and allow the lips to relax and gently come together
When adult teeth erupt, they tend to erupt with a distal migration. True or False?
False. A mesial migration.
What is the concept of serial extraction?
- It was kjellgren in 1929 who 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.
- -The primary 1st molar is extracted, which then helps the first premolars erupt, and then you extract them as well
What are the main assumed disadvantages of extraction treatment in orthodontics?
- Non-extraction treatment is held by some to always be better than extraction.
- Non-extraction treatment is thought to improve the facial profile and appearance of orthodontic patients.
- Claims of detrimental facial appearance due to extraction include:
– Flat lips and retracted sunken in incisors
• If the anterior teeth are retracted to closet he extraction space, lip support is lost and can create a flattening of the lips and a sunken in incisor look.
– Narrow arch widths with large buccal corridors.
• It is believed that if you extract teeth then the dental arches must be constricted, which can create large buccal corridors.
What three main factors affect facial appearance?
- Genetic Makeup
- Environmental influences
- Cultural background
What did the North Carolina study conclude about the attractiveness of extraction vs non extraction patients?
They concluded that there was no difference in attractiveness between extraction and nonextraction patients.
• It was concluded that extraction had a positive effect on the profile of patients with some combination of crowded and proclined teeth,
• Whereas nonextraction therapy had a detrimental effect on the profile
– This patient didn’t like the angulation and protrusion of her front teeth which caused the patient to have to strain to get her lips to touch.
• You can see the dimpling of the patients chin referred to as mentalis strain with lip incompetence.
– The patient was treated with non extraction therapy as a teenager and was never happy with the results.
– After consultation and analysis the patient decided to have four premolars extracted, to relax the lip incompetency and retract the incisor position.
How does proclining the mandibular incisors during treatment affect the periodontal status?
– Proclining the mandibular incisors more than 95° with decreased gingival thickness of less than .5 mm increased the severity and the amount of recession.
– This is a significant disadvantage for nonextraction patients with crowded mandibular incisors.
It now is claimed that expansion of the mandibular arch is stable if the maxillary arch is expanded, but no evidence supports this. True or False?
True
For the best treatment outcomes, some patients need non- extraction treatment, some need extractions, and a key goal of diagnosis is gathering data on which to base this decision, not on which bracket to use. True or False?
True
What are the characteristics of lower incisor extractions?
• Sometimes an orthodontist will order the extraction of a lower incisor.
• This is typically due to a tooth size discrepancy
• This treatment option is sometimes elected if an adult has mandibular incisor crowding with recession and bone loss on a protrusive incisor.
• Draw backs to lower incisor extraction treatment:
– Patient will have to be finished with a deeper bite (over-bite).
– Patient often will have some over-jet once the case is finished.
– Canine guidance is sometimes difficult to achieve.
• A full orthodontic work up and analysis must be performed, weighing the pros and cons before extraction of any tooth, especially a lower incisor due to the typical compromised results.
When are second molar extractions used?
With class II cusp and jaw relationships, anterior open bites, and severe thumb-sucking habits.
ANY tooth could be extracted for orthodontic purposes. True or False?
True
What is root burial?
• Because erupting teeth bring bone with it, orthodontic tooth movement can be used to create the alveolar bone needed to support an implant to replace a congenitally missing tooth.
– Missing maxillary lateral incisors or mandibular second premolars
• Root Burial is leaving a tooth in place, or its root, to help maintain bone in the area until an implant can be placed
Why is the mesial drift of a canine with a missing lateral incisor beneficial?
Because it will bring alveolar bone with it. • 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 left in place and lateralized to replace the missing lateral incisor.
Canine substitution typically has the best results when only one canine is used to substitute for the missing lateral incisors, to help maintain arch width and length. True or False?
False.
- Canine substitution typically has the best results when both canines are used to substitute for the missing lateral incisors, to help maintain smile symmetry
What are the characteristics of replacing missing maxillary lateral incisors with implants?
- If implants are to be used to replace the missing lateral incisors it is advantageous to allow the maxillary canine to erupt into the lateral incisor position and then orthodontically distalize the canines, which increases the bone in the lateral incisor area for the future implant
- Missing lateral incisors must have the spaces maintained until implants can be placed once growth is completed.
- Retainer to replace missing teeth
- Bridges
- Maryland bridge
- Tooth bonded to permanent retainer
- Composite bridge
How are missing mandibular second premolars most often fixed?
• Close space orthodontically
– Temporary anchorage device (TAD)
• Bridges
• Implants
– Retention until implant can be placed
-If they don’t have a lower wisdom tooth, then it wouldn’t be ideal to bring all of the molars mesial.
When treating peg laterals, orthodontics should center the peg lateral. True or False?
True
When re-building a peg lateral, how large should it be?
- Measure the opposite side lateral incisor, if the tooth is present to determine size and shape
- If both lateral incisors are missing, the width is determined by using 2/3 size of the central incisor as a guide.
- The length should be 80 percent the length of the central incisor
- Gingival height of the lateral should be 1mm lower than the gingival height of the central incisor and canines.
Maxillary lateral incisors are the second most commonly impacted or displaced tooth behind the third molars. True or False? And what are the percentages?
False, it is maxillary canines.
• Impaction occurs in about 0.8 to 2.4 percent of the U.S. population and is significantly more common in females than males (about 2:1)
• In more than 90 percent of the cases impaction usually involves a single maxillary canine, however impactions are also seen bilaterally in 8 percent of the patients.
• The majority of impacted canines are displaced toward the palatal aspect, but 20 percent occur toward the facial aspect.
What are the main six 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
For impacted canines, 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. True or False?
True. An implant with a crown or bridge can be used to replace the missing tooth.
If the canines are not overlapping the lateral incisors but are erupting mesially, pushing on the lateral incisors root, tipping the root mesially, what are the steps being evaluated and prescribed by the orthodontist to try to help the eruption path of the maxillary canines?
- Extraction of the maxillary deciduous canine. This 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
- 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
- However, in some situations, even these techniques do not work, and the orthodontist must refer the patient to have the impacted canine uncovered surgically
What are the three problems when considering an unerupted tooth that must be surgically exposed?
- Type of surgery
- How to attach to the impacted tooth
- Ortho mechanics to bring the tooth into the dental arch
What are the three surgical techniques for uncovering an impacted maxillary canine?
- Gingevectomy
- Apically positioned flap (One of the cons of #2 is you are getting rid of the attached gingiva, so they are prone to periodontal problems later in life)
- Closed eruption technique
Why is it critical for the orthodontist, that the oral surgeon bond to the buccal surface of the impacted canine or as close to the occlusal tip as possible?
• If the attachment is bonded in the incorrect position the
canine will come in sideways or worse backwards
What are the root complications of having erupting canines or really any tooth?
- Ectopic eruption of canines (or any tooth) may cause severe root resorption of adjacent teeth
- Early screening and diagnosis are essential
- Since resorbed incisors are mostly free of pain, early detection by radiographic examination is essential to establish proper diagnosis.
- Angulation of the canine is important
- A 25 percent increase in the eruption angle of the canine relative to the lateral incisor, increases the risk of resorption of the lateral incisor by 50 percent
- Rimes and colleagues have shown that the problem often is diagnosed late, both in relation to the patient’s age and to the extent of the resorption. They suggest that dental practitioners may underestimate the problem.
When should you refer in regards to maxillary canine ectopic eruption?
- As soon as you see mesial movement of the maxillary canine and especially if the canine is disrupting the angulation of the maxillary lateral incisor, immediate referral and evaluation by an Orthodontist is critical. (When in doubt, send it out:)
- American Association of Orthodontists recommends that all children be evaluated by an orthodontist by the age of 8 years old
Treatment for older adults has been the fastest growing area in orthodontics during the last decade. True or False?
True
Growth modification, camouflage, and surgical options are all possible treatment options for adult orthodontics. True or False?
False. Adult treatment is more difficult due to the absence of growth, which means that growth modification to treat jaw discrepancies is not possible, which leaves only camouflage or surgical options available to the orthodontist.
What two steps are required for planning limited adult ortho treatment?
- Collecting an adequate diagnostic data base
2. Developing a comprehensive but clearly stated list of the patient’s problems.
What are the main goals of limited adult ortho treatment?
– Improve periodontal health by eliminating plaque harboring areas and improving the alveolar ridge contour adjacent to the teeth
– Establish favorable crown-to- root ratios and position the teeth so that occlusal forces are transmitted along the long axes of the teeth
– Facilitate restorative treatment by positioning the teeth so that:
• More ideal and conservative techniques (including implants) can be used
• Allowing optimal esthetics to be obtained through bonding, laminates, or full coverage porcelain restorations
An adults orthodontic records should ALWAYS include a FULL set of full mouth x-rays. True or False?
True
A teenagers orthodontic records should ALWAYS include a FULL set of full mouth x-rays. True or False?
False, their bone and periodontal health is usually pretty good.
What happens to the adjacent teeth when a first permanent molar is lost?
When a first permanent molar is lost and is not replaced, the second molar typically drifts mesially and the premolars often tip distally and rotate into the space between them
- As the teeth move the adjacent gingival tissue becomes folded and distorted, forming a plaque harboring pseudopocket that may be virtually impossible for the patient to clean
What are the two main orthodontic options for treating the consequences of losing a permanent first molar?
• Uprighting a tipped molar by distal crown movement leads to increased space for a bridge pontic or implant. This is a more common approach because it’s easier.
• Whereas uprighting the molar by mesial root movement reduces space and might eliminate the need for a prosthesis
– but this tooth movement can be very difficult and time- consuming to accomplish
– especially if the alveolar bone has resorbed in the area where the first molar was extracted and cortical bone has filled into the extraction site
What is the best option for treating a lost permanent first molar with a third molar present behind it?
- For many patients distal positioning of the third molar would move it into a position in which good hygiene could not be maintained or it would not be in functional occlusion.
- In these circumstances, it is more appropriate to extract the third molar and simply upright the remaining second molar tooth.
- If both molars are to be uprighted, a significant change in technique is required and treatment time will also be significantly increased
What does uprighting a tipped molar do to the crown height and depth of the mesial pocket?
It increases the crown height while reducing the depth of the mesial pocket.
Reducing the height of the molar crown by shaving it down is a routine part of molar uprighting. True or False?
True. Crown reduction decreases occlusal interference and also improves the ratio of crown height to supported root length of the molar.
– This will also improve the mesial pseudopocket, as well as forces along the tooth.
What are the eight guidelines that the dental team should follow when planning interdisciplinary treatment?
- Realistic objectives
- Create a diagnostic set-up
- Determine the sequence of treatment
- Stabilize/ correct any active disease
- Position teeth to facilitate restorative treatment
- Evaluate gingival esthetics
- Take progress radiographs
- All members interact during finishing
How are one wall periodontal defects best treated?
• One wall defects are the type which are treated most efficiently by the orthodontist.
– In these situations, periodontal pathogenic bacteria have destroyed the attachment on three of the four interproximal walls, leaving one wall remaining.
• One wall defects are difficult for a periodontist to manage, because resective surgery could be too destructive, and regenerative therapy is inappropriate.
• Orthodontic eruption of the tooth can eliminate these defects
How are two wall periodontal defects best treated?
• Two wall periodontal defects are best treated with periodontal surgery with or without adjunctive orthodontics
– When two walls are remaining in an inter-proximal region, and the patient cannot maintain the area, it is difficult for a periodontist to completely resolve the defect with resective or regenerative treatment.
– These defects often require orthodontic eruption of the affected tooth, followed by crown lengthening to improve the restorability of the tooth.
How are three wall periodontal defects best treated?
– Three wall defects are not resolvable with orthodontics. These defects are generally treated with regenerative therapy, using either autogenous or alloplastic bone grafts in the affected area.
– Orthodontic treatment can begin 6 months after placement of the bone graft and the area has been shown to be stable.
When orthodontic brackets are placed on an adult patient, the decision as to where to place these brackets or bands is not determined by the interproximal bone level, but rather by the anatomy of the tooth. True or False?
False, it is backward. When orthodontic brackets are placed on an adult patient the decision as to where to place these brackets or bands is not determined by the anatomy of the tooth but rather by the interproximal bone level.
If the bone level is oriented in the same direction as the marginal ridge discrepancy, then leveling the marginal ridges will level the bone. True or False?
True.
- However, if the bone level is flat between adjacent teeth and the marginal ridges are at significantly different levels, correction of the marginal ridge discrepancy orthodontically produces a hemiseptal defect in the bone.
• This could cause a periodontal pocket between the two teeth
- Whenever possible the bone should be leveled orthodontically and any remaining discrepancies between the marginal ridges should be equilibrated.
• This method produces the best occlusal result and improves the periodontal health
• Patients should be seen every 2 – 3 months by their dentist or periodontist during the leveling process to control inflammation in the interproximal region
If an adult patient has considerable gingival recession and bone loss, would it be more effective to alight the crowns of the teeth orthodontically, or to align the teeth so their bone level is at the same level?
• By aligning the crowns of the teeth, the clinician may perpetuate tooth mobility by maintaining an unfavorable crown to root ratio.
– Also by aligning the crowns of the teeth and disregarding the bone level, significant bone discrepancies occur between healthy and periodontally diseased roots, which could require periodontal surgery.
• Many of these problems can be corrected by using the bone level as a guide to position the brackets on the teeth.
• In these situations, the crowns of the teeth may require considerable equilibration but:
– Bone health
– Periodontal health and
– Crown to root ratios will all be improved and the patient may not require periodontal surgery.
What type of lesions are the most difficult to maintain and can worsen during orthodontic therapy?
Furcation lesions
What are the three furcation classifications?
– Class 1 – Very shallow and do not enter the furcation deeply. These are typically just observed and monitored during orthodontic treatment
– Class 2 – Extend into the furcation but does not completely go through
– Class 3 – Lesion goes completely through the furcation.
If a patient has a class III furcation and is to be undergoing ortho treatment, what are the steps taken?
• If the patient is to be undergoing orthodontic treatment the tooth is moved first and then the tooth is hemisected after treatment is complete. • A patient with a class 3 furcation can be treated by eliminating the furcation by hemisecting the crown and roots of the tooth. – (works well for mandibular molars) but this procedure requires endodontic, periodontal and restorative procedures. • This treatment is an option that should be considered in special circumstances, but implants may be a better alternative to hemisecting treatment.
What are the two ways for clinicans to address long term incisal wear with subsequent overeruption (short clinical crowns and disproportionate marginal gingiva)?
- Crown lengthening
2. Orthodontic Intrusion
What are the advantages of performing orthodontic intrusion for short clinical worn down crowns rather than crown lengthening?
• Crown lengthening exposes cementum and subsequently requires a more invasive, full coverage restoration.
• Orthodontic intrusion provides the potential benefit of limiting the restored area to enamel and often results in a more conservative bonded veneer restoration
– Orthodontic intrusion is beneficial restoratively only if the bone level and gingival margin follows the tooth as it moves apically, which in the absence of disease is what happens.
Why can opening the patient’s vertical cause problems for worn down teeth?
• Although some clinicians believe that patients with anterior tooth wear are “overclosed” and need to have their vertical dimension increased, this diagnosis and the resulting treatment plan are usually inappropriate.
• The problem typically is compensatory eruption of the anterior teeth, secondary to incisal wear.
• The problem for the restorative dentist is that there is insufficient space to restore these teeth without further:
– Tooth reduction,
– Crown lengthening and
– Root canal treatment
What are the considerations with patients that have severe attrition of the mandibular anterior teeth and insufficient crown length to either place an ortho bracket or to permit adequate ferrule for tooth preparation?
• In these situations periodontal surgery and crown lengthening prior to orthodontic intrusion may be appropriate.
• If there is not 1.5 to 2.0mm of ferrule then crown lengthening surgery should be performed first to establish adequate ferrule then the teeth should be intruded orthodontically to create the correct vertical position prior to restoration.
– This will provide access to bond orthodontic brackets to intrude the teeth.
How do you correctly determine a patient’s correct occlusal plane?
• To do this you identify the occlusal contact point between the maxillary and mandibular second molars posteriorly and the level of the patient’s upper lip at rest anteriorly. These reference points are points that cannot be changed but that are important to stability and esthetics
Opening the vertical dimension by extruding maxillary and or mandibular molars is stable in adults. True or False?
False, it is not, since adults are not growing.
-– The muscles of mastication do not have the capacity to stretch in adults and attempts to increase posterior facial height with orthognathic surgery have consistently been unstable, and the vertical dimension usually reverts to its original level.
• That is not to say that there are not occasions when patients are overclosed and opening the vertical dimension is appropriate.
• But special care must be taken so that when the patients vertical is opened there is not an impingement on the patients freeway space, which is typically 2-4mm.
• If the treatment plan involves opening a patients vertical, every tooth will need to be crowned/restored, be sure to evaluate crown to root ratios.
– These patients are best treated by a prosthodontist and these cases should be referred out.
What is a possible treatment on teeth that have fractured the crowns that extend beneath the level of the gingival margin and terminate at the level of the alveolar ridge?
- If a patient severely fractures the crown of their tooth, the general practitioner must evaluate if the tooth can be restored or if the tooth must be extracted.
- Orthodontic forced eruption should be considered in these situations as a possible treatment, to aid in the restoration of these teeth.
- Without forced eruption, these teeth are destined for extraction or periodontal crown lengthening procedures, which often result in long unaesthetic teeth with visible restorative margins.
