Open bite

WELCOME

Presented by:Dr. Md. Ishtiaq Hasan

BDS, FCPS-II Trainee,Dept. of Orthodontics, DDCH

Supervisor:Prof. Dr. Md. Zakir Hossain

BDS, PhD(Japan)Prof. & Head,

Dept. of Orthodontics,DDCH.

Orthodontic treatment of dental open bite: A case report

HISTORY AND DIAGNOSIS• 35 years old female came to the department of

Orthodontics and Dentofacial Orthopedics, Dhaka Dental College and Hospital with the chief compliant of unpleasant aesthetic look due to spacing and proclination of upper jaw.

• The patient was in the permanent dentition.• She had no relevant dental, medical or family history • No history of previous orthodontic treatment.

extra oral examination

Facial photo-Frontal view

Facial photo-Right view Facial photo-Left view

A convex profileLips are incompetent at rest showing 75% of the upper central incisorsLower midline shifted 2 mm right sideShe had obtuse labiomental angle She had increased lower facial height

Intraoral examination

Facial photo-Right view

Facial photo-Frontal view

Facial photo-Left view

She had an anterior open bite from right sided lateral incisor to left sided lateral incisor

Missing Grossly carious Canine relationship class-II on right side and class-I on left sideOverjet. 9 mm

6 565

Radiological Examination

Panoramic radiographs revealed that missing right sided second premolar, first molar and left sided first molar.Grossly carious right sided first premolar Generalized bone loss. There was no bony pathology

Radiological Examination

• Cephalometric evaluation showed—Variables Values Bangladeshi norm Clinical norms Differences

SNA 79.1° 83° 80.0..89.0° -2

SNB 72.1° 81° 75.0..82.0° -9

ANB 7.0° 2° 2.0..4.0° +5

SND 69.0° 79° 76.0..77.0° -10

IIA 96.6° 117° 130.0..150.0° -21

SN-OcP 21.4° 13° 14.0° +8

SN-GoGn 46.4° 25° 30.0° +21

Max1-NA 33.5° 29° 22.0° +4

Max1-SN 112.7° 108.0° +4.7

Mand1-NB 42.9° 30° 25.0° +12

1u-NA 6mm 8mm 4mm +2

1l-NB 6mm 8mm 4mm +2

Holdaway Ratio 8mm 0..2mm +6

S-L 14mm 59mm 51mm -45

S-E 11mm 23mm 22mm -12

ANB angle is more than normal and IIA is less than normal. So, it is a case of skeletal class 2 div I.MPA angle is more than normal (+21), so patient is hyperdivergent.

Aetiology• Patient history revealed that she had thumb

sucking habit, suggesting that anterior open bite etiology was related to thumb sucking.

• No respiratory problems were noted.

WHAT ARE THE CAUSES OF ANTERIOR OPEN BITE AND WHY RELAPSE OCCUR

• Teeth & alveolar bones are balanced by the forces of lips, cheeks and tongue. If this balance is altered, changes occur.

• Based on this idea of balance, several etiological factors are associated with AOB.

• The severity of AOB and sucking habits of fingers and pacifiers have been well established.

• In such cases, AOB self-corrects consistently after removal of habits, provided that no other secondary dysfunctions have set in.

• The secondary dysfunctions may developed from maxillary incisor protrusion generated by the sucking habit, thereby breaking the lip seal required for swallowing and causing the tongue to be abnormally positioned, especially at rest.

• Hypertrophic lymphoid and tonsils are the most common cause of nasal obstruction and consequently may force the tongue to remain lower to allow breathing to occur through the oropharyngeal rather than nasopharyngeal space.

In 1964, Subtelus and Sakuda published an article on the diagnosis and treatment of AOB. They try to find out an explanation for the existence of persistency of open bite after removal of the causes. They found that in case of persistent open bite, the following significant differences were found---

• Greater eruption of upper molars• Extrusion of upper incisors• Increased mandibular plane and gonial angleThey named this facial pattern as ‘skeletal open bite’. Its primary etiological factor is an unfavorable growth pattern with divergent

basal bones and therefore no contact between the incisors. These etiological factors are associated with growth and not function and can

thus be defined as skeletal factors.

• Over the years, vertical facial pattern was ultimately considered as the main risk factor for AOB and treatment stability. However, other studies have reported that most hyperdivergent pts exhibit a normal or deepbite while pt with normal facial patterns display a persistent open bite.

So, skeletal pattern cannot be the cause of AOB.

• Denison et al. assessed the stability of surgical treatment in 66 adult pts followed up for at least 1 year after surgery. They found 42.9% of open bite cases recurred and the relapse was due to dentoalveolar changes and not for the skeletal changes.

• Once hyperdivergency is successfully eliminated with orthognathic surgery, it cannot be blamed as an etiological factor for open bite relapse, because these pts were adult, & exhibit no growth.

• Therefore, it is believed that causes of relapse in AOB are due to dentoalveolar origin, generated by oral disorders, overlooked in the pretreatment phase.

• Most investigations of AOB etiology agree on the existence of secondary dysfunction, which remain after the correction of etiology , such as stop thumb sucking or removal of adenoids and tonsils. This secondary dysfunction is poor tongue posture at rest.

• Lower tongue posture at rest exert a long lasting pressure on teeth, prevent eruption of incisors, thereby causing and maintaining AOB.

• In addition, a low tongue posture may encourage the eruption of posterior teeth and constrict the upper arch since the tongue does not touch the palate.

• This etiological factor may not been studied enough and is generally overlooked during AOB treatment.

• Failure to eliminate this factor may be the key reason of AOB relapse.

Different types of the tongue at rest:

• The normal position of tongue is it rest on the incisal papilla and its back lies along the palate, keeping the anterior teeth in balance while preserving the transverse dimension of the upper arch.

• Tongue shows 4 types of abnormal resting posture—high, horizontal,low and very low.

High posture: • High posture of the tongue at rest is

associated with slightly protruded upper incisors and AOB may exhibit vertical overlap and positive horizontal overlap.

• Since the tongue rests on the palatal surface of the incisors, beneath the incisal papilla, upper incisors are positioned above the occlusal plane.

• Leveling of the mandibular arch is unaffected and display a single occlusal plane.

• Posterior crossbites are not present as the back of the tongue rests on the palate while maintaining the transverse dimension of the upper arch.

High posture of the tongue at rest, associated with a mild AOB; may exhibit vertical overlap. The maxillary incisors are protruded and lower arch leveling is unchanged. No posterior crossbite was observed. The arrows represent the direction of the force exerted by the tongue.

Horizontal position: • In the horizontal posture of

the tongue at rest, the tongue appears lower than in the high position, although with greater protrusion, resting on the palatal surface of the upper incisors and on the incisal edges of the lower incisors.

• The major effect in this case can only be seen in the upper arch, where protrusion of maxillary incisors was more prominent, which prevented their extrusion, thereby causing AOB.

• Also due to the greater protrusion of the incisors, a positive and increased horizontal overlap was noted.

• As the tongue positions itself lower, its back turns away from the palate allowing transverse changes to occur in the maxillary arch, which may cause posterior crossbites.

Horizontal posture of the tongue at rest, associated with a moderate AOB; may exhibit vertical overlap.

The maxillary incisors are markedly protruded and above the occlusal plane.

Lower arch leveling is unchanged.

Due to the distance between the back of the tongue and the palate, posterior crossbites may emerge.

The arrows represent the direction of the force exerted by the tongue.

Lower position: • As the tongue assumes a lower

position, pressure begins to be exerted on mandibular teeth.

• In the low posture of the tongue, it rests on the lingual surface of the crowns of mandibular incisors, thereby protruding these teeth and preventing their eruption, which establishes a moderate open bite.

• Due to protrusion in the lower incisors, horizontal overlap may be zero or negative.

• A gap can be seen between the occlusal surfaces of posterior teeth and the incisal surfaces of anterior teeth in the lower arch only, with lower incisors positioned below the occlusal level.

• Posterior crossbites may be present for the same reason mentioned above.

Low posture of the tongue at rest, associated with a moderate AOB. The mandibular incisors display a pronounced protrusion. Lower arch leveling is changed, with mandibular incisors positioned below the occlusal level. Due to the distance between the back of the tongue and the palate, posterior crossbites may emerge. The arrows represent the direction of the force exerted by the tongue.

Very low position: • A very low tongue posture occurs when the

tongue rests below the crowns of the mandibular incisors in the lingual region of the lower alveolar ridge.

• The direction of tongue pressure produces retroclination of mandibular incisors and prevents their eruption, positioning them below the occlusal level.

• The open bite is more severe and associated with posterior crossbite due to the fact that the tongue moves away from the palate.

• The tongue sprawls across the mouth floor, expanding the lower arch in the transverse direction.

Very low posture of the tongue at rest, associated with a severe AOB. The mandibular incisors appear uprighted or retroclined. Lower arch leveling is changed, with mandibular incisors well below the occlusal level. Due to the distance between the back of the tongue and the palate, posterior crossbites are bound to emerge. The arrows represent the direction of the force exerted by the tongue.

High Upper proclineLower no change (IMPA normal)Vertical overlap presentNo cross bite

Horizontal Upper more proclineLower no change (IMPA normal)Vertical overlap presentPost cross bite

Low Lower proclineNo overlapLower incisors present below occlusal levelPost cross bite

Very low Lower retroclineLower incisors present below occlusal levelPost cross bite

Treatment choices based on tongue position at rest :

• High and horizontal tongue postures are positioned very close to normal posture and require control in the horizontal direction only.

• It is suggested that blocking mechanisms such as cribs are sufficient to produce this tongue retraction and adapt it to its correct posture at rest. This type of treatment will be referred to as restraining treatment.

• However, in the low and very low tongue postures, the tongue is not only protruded but it is positioned below its correct position and needs to be retracted and elevated.

• This process is difficult to learn and automate, requiring educating devices which force the direction of the tongue, such as spurs. This type of treatment will be referred to as orienting treatment.

APPLYING CRITERIA FOR AOB DIAGNOSIS AND TREATMENT: CASE REPORT

Case 1: high posture of tongue at rest

8 years old female ptMixed dentition stageAngle class I malocclusion with AOBSlightly increased overjetProtruded maxillary incisorsInterincisal diastema in the upper archThe lower arch was normalFace was symmetrical with slightly convex profile

• Patient history did not reveal sucking habits, indicating that AOB was caused by an abnormal posture of the tongue at rest.

• AOB morphological characteristics indicated that the patient had a high tongue posture as it did not change the occlusal plane in the lower arch.

• However, the maxillary incisors were protruded and positioned above the occlusal plane.

• Since the treatment goal was to restrain the tongue in the horizontal direction, placing it further back, restraining treatment was preferred and a Hawley retainer was therefore used, combined with a crib.

• The retainer was used for a period of two years until the patient was in the final stage of mixed dentition.

• She was monitored until the permanent dentition phase. The AOB was closed, overjet and interincisal diastemas reduced. No other treatment was performed on this patient, who achieved a stable result as can be seen from the records obtained 32 years after treatment.

• It was only thanks to the removal of a poor tongue posture that establishing a normal horizontal overlap became possible and, more im- portantly, the AOB etiological factor was eliminated, thus ensuring a stable result for many years.

Hawley retainer with crib used to treat patients for a two year period until a normal overbite was attained.

Extraoral and intraoral photographs 32 years after treatment

Case 2:Horizontal Posture of tongue at rest

9 yrs old female ptMixed dentitionAngle class II div 1 malocclusion8 mm overjetCrossbite presentAOBMidline shifted to the right less than 2 mm

Symmetric faceConvex profileSkeletal pattern class II (SNA =88,

SNB=78, ANB= 10)Mandibular plane angle normal (MPA 34)

• Patient history revealed that she had no sucking habits, suggesting that AOB etiology was related to abnormal tongue posture.

• To determine what sort of tongue posture the patient had it was observed that lower arch leveling was normal while the upper incisors were protruded and positioned above the occlusal level. These features suggest a horizontal posture of the tongue associated with marked overjet. Therefore, restraining treatment would be indicated in this case.

• It was decided to use head gear (As incisors are proclined), expansion screw (for crossbite) and palatal crib (For AOB), which was worn for six months.

• After this period, an Angle Class I molar relationship was attained with 3 mm overjet, the crossbite was corrected as well as the AOB and there was improvement in the skeletal relationship (SNA=83°, SNB=78° and ANB=5°). The face remained symmetrical and the profile slightly convex . The appliance was then worn only at night for another six months for retention purposes.

• At age 12, the second phase of treatment was initiated with the placement of a fixed metallic orthodontic appliance.

headgear used in the first treatment phase containing a posterior maxillary splint with an expansion screw, lingual crib and Hawley clasp.

Extraoral photographs, cephalometric radiograph and intraoral photographs at the end of the first treatment phase.

Extraoral and intraoral photographs at the end of the second treatment phase.

In this case, AOB correction occurred, thanks to a spontaneous extrusion of the incisors after using a palatal crib and correcting the tongue posture. The results were stable as can be seen in the follow-up photographs 10 years after treatment.

Stability of AOB correction was accomplished because the etiological factor was eliminated.

EXTRAORAL AND INTRAORAL PHOTOGRAPH 10 YEARS AFTER TREATMENT.

Case 3: High Posture of tongue at rest

7 years old femaleMixed dentitionClass I molar relationshipTendency toward posterior crossbiteAOBThe face was balanced with no apparent asymmetriesLip incompetence

Convex profileSkeletal class I (SNA=78, SNB=77, ANB=1)

• No sucking habit was reported.• The morphological features of this AOB

included slightly protruded maxillary incisors with deficiently erupted and protruded mandibular incisors (IMPA=100°)

• These effects in the lower arch suggest a low posture of the tongue at rest.

• Since this tongue had to be retracted and elevated, it was decided to conduct orienting treatment with spurs on the lingual arch.

• The spurs were worn for a period of two years and the patient monitored for another two years until the permanent dentition stage.

• By then the patient had developed a Class I molar relationship, severe lack of space in both arches, posterior crossbite on the right side, and normal overbite.

• The mandibular incisors were uprighted and extruded through the use of spurs (IMPA=92°).

• The skeletal Class I relationship was maintained (ANB=1°). Corrective treatment was then initiated with extraction of first premolars.

Panoramic radiograph of patient with spurs in place, reorienting the tongue backwards and upwards.

Extraoral photographs, cephalometric radiograph and intraoral photographs after use of spurs in permanent dentition. uprighting and

extrusion were attained in the lower incisors with the use of spurs alone, and the stable outcome was monitored over 5 years.

Extra oral and intraoral photographs at the end of corrective treatment after 7 years of spur use, showing stability of AOB correction.

Case 4: Very low Posture of tongue at rest

9 years old female patientSevere AOB and severe lack of space in lower archShe was a mouth breather and undergo speech therapySkeletal class III (ANB= -1)Vertical growth pattern and MPA=49

• According to the morphological characteristics of the open bite, the patient had a very low position of the tongue at rest, clearly characterized by retroclination of mandibular incisors (IMPA=70°) and posterior crossbite.

• To perform the correction it would be necessary to move the tongue upward and backward with orienting treatment.

• The appliance of choice was a lower lingual arch with spurs.

• Firstly, a single spur was placed in the midline region, then other spurs were gradually inserted in the canine-to-canine region.

• Use of lingual arch with spurs was suspended four years later. At this time a significant improvement in vertical overlap was observed as well as the presence of diastemas in the mandibular incisor region due to the protrusion of these teeth. The profile remained balanced and the face symmetrical . At this stage, it was decided to place a fixed orthodontic appliance in the mandibular arch in order to close spaces.

• The upper arch received no appliances and was monitored for a period of one year to assess stability of AOB correction. Should the AOB have relapsed it would have meant that the tongue posture had not been corrected. An adequate vertical overlap was achieved and the posterior crossbite corrected.

Spurs used on lingual arch, start- ing with one spur at arch center (A) and increasing number and size of spurs (B) in order to reorient tongue posture backwards and upward.No expansion was performed in the upper arch

and crossbite was corrected by positioning the tongue higher, thus changing the transverse dimension of the arch. The face remained symmetrical with a balanced facial profile. At this stage, fixed appliances were installed in the upper jaw to finish the case.

• Correction of this AOB was achieved mostly by a significant extrusion of the mandibular incisors The backward and upward change in tongue posture allowed eruption of the incisors, thereby lengthening the alveolar process , as reported by Meyer-Marcotty et al. The skeletal features of this face would have one believe that the cause of the AOB might be an unfavorable growth pattern. However, this case suggests that AOB occurs — even in hyperdivergent faces — when the eruptive process is hampered by a mechanical obstruction (in this case the tongue), and thus, skeletal pattern would not play an etiological role in AOB.

Extraoral and intraoral photographs after 4 years of spur use.

intraoral photographs after placement of appliance in the lower arch.

cephalometric x-rays comparing initial and final treatment phases. Radiographs shows protrusion and marked extrusion of incisors obtained with the use of spurs only.

Removal of the causative agent of this AOB ensured outcome stability 10 years after treatment. Treatment of these cases requires patience and the long-term use of spurs, which in this case lasted for 4 years. Due to AOB severity, the amount of extrusion required for incisors to attain vertical overlap is considerable . Moreover, the process of automating tongue posture is slow, demanding time for neuromuscular restructuring.

Extraoral and intraoral photographs 10 years after treatment.

Palatal or lingual crib:• They are aimed to correct AOB by

preventing the tongue from resting on the teeth.

• They must be long to prevent the tongue from positioning itself below them but it fails to re-educate the tongue.

• In this case, the tongue return to its original position when it is removed, thus leading to AOB relapse.

Palatal or lingual spur:• It was described by Rogers in 1927 in the treatment of 3 open

bite cases. • Spurs induce a change in the resting position of the tongue,

thus allowing tooth eruption and openbite closure. • This change in tongue position alters sensory perception by the

brain, thereby producing a new motor response. This response can be imprint permanently in the brain, which explains the permanent change in tongue posture produced by spurs. This is the main factors responsible for AOB treatment stability.

• Crib without spur simply restrain and does not retrain the tongue, while spur discourage the tongue from resting against them. A spur appliance is more effective in arresting finger habits and correcting AOB than crib without spur.

• Huang et al. evaluated AOB treatment stability using spurs in 33 patients divided into 2 groups, one with and one without growth and they found that AOB correction occurred in both cases.

Clinical recommendations:

• Spur appliance should be non-removable.• It should remain in the mouth at least 6 months after the AOB

has ceased.• Spur is constructed with .045 inch ss wire (similar to a

mandibular lingual arch) to which eight short, sharpened 0.026 inch spurs, 3 mm in length, are soldered from canine to canine.

• The spurs are positioned 3 mm away from the cingulum of the incisors and are directed at an angle (downward & backward) to encourage correct tongue posture, with the tip of the tongue behind the upper central incisor papilla.

• The AOB usually takes 6-8 months to close after appliance cementation but may take a longer time for some patient.

• At the end of active orthodontic treatment without bonded spur appliance, a removable appliance with spurs will not be successful. In that cases, fixed spurs should be given because patient cannot wear removable spur appliance full time and part time wearing of a removable spur appliance is not effective in closing open bites. It takes 2-3 weeks for patients to adopt to speaking, swallowing and eating with cemented spurs. Therefore , it is reasonable to expect patients who have never used fixed spurs to wear a removable spur appliance full time until the bite closes.

• To avoid making patient afraid, Dr. Roberto Justus advised to refer the spur appliance as ‘the reminding appliance’ in front of the patient.

• A mandibular spur appliance is as effective as maxillary one, except that it is visible and patient might find it objectionable since they should be continuously asked about the appliance.

• Haryett et al. concluded that spur appliance do not cause psychological problems and there are no reports of pain or injury to the tongue and no marks or bruises can be seen on the tongue when using spurs.

• When cementing the spur appliance, the family should be informed that there will be some initial difficulty speaking, eating, and swallowing. All of these problems will be resolved in 2 to 3 weeks. During this period, patients are asked to cover their spurs with cotton. The tongue is thus protected and can gradually adapt to the spurs.

• The patients should also be advised to pay particular attention to hygiene on the lingual aspect of the maxillary incisors because the spur appliance makes brushing this area more difficult.

When an orthodontist is faced with an anterior open bite relapse, Dr. Roberto Justus recommends the following-----

• Explain to the family the possibility that the relapse is due to an anterior tongue rest posture problem.

• Determine whether orthognathic surgery is indicated or not.

• If surgery is not advisable, recommend a cemented reminding appliance with spurs.

• Encourage the family by giving them a copy of an article that shows cases successfully treated with the spur appliance.

• A mandibular canine to canine fixed retainer or a removable lower retainer is given to avoid incisor crowding.

• Bond a upper canine to canine retainer to ensure that the maxillary incisor alignment is maintained.

• Allow the spur appliance to remain in the mouth for at least 1 year, even though the bite may have closed in 6 to 8 months.

• Do not expect the bite to close immediately.

Contra-indications of spur appliance---• Diminished muscular control.• Abnormally large tongue.• Maxillary lateral incisors have not yet erupted (indicating that closing a

transitional anterior open bite).• Stressful periods in patient/parents lives (illness, divorce, school exams, etc).• Immaturity (lack of understanding treatment goals).• Increased nasal resistance, allergic rhinitis, or enlarged tonsils and/or

adenoids (particularly during an acute episode).• Ongoing speech therapy. Speech therapy should preferably be instituted after

the bite has closed because the speech therapist can work more effectively with a child who does not have an anterior open bite.

• Bad oral hygiene.• Severe skeletal dysplasia (need orthognathic surgery).

Orthodondic or surgical treatment of AOB?

• Surgical treatment is indicated for extremely severe cases with MPA above 50

• In orthognathic surgery cases, spur appliance should be considered post-surgically and only if an open bite begins to relapse.

TREATMENT OBJECTIVESConsidering the above findings the objectives of orthodontic

treatment of this patient were to –• Correction of anterior open bite.• Correction of median diastema.• Reduce lip procumbancy and lip incompetency.• Retrocline upper and lower incisors.• Establish normal overjet and overbite.• Establish normal interincisal angle.• Correction of midline.• Improve gingival condition.• Improve profile• Establish and maintain occlusal harmony and interdigitation

for improved aesthetics and proper function.

TREATMENT PLAN AND PROGRESS

• Due to badly destruction of lower right first premolar, it was decided to extract the tooth.

• The treatment plan was to extract both upper first bicuspids to retrocline upper incisors and reduce lip incompetency and distal movement of lower right canine and left premolars.

• But patient refused to extract teeth as because she already lost so many teeth.

• So we try to retract upper incisors and reduce lip incompetency as much as possible by utilizing the space available between the upper incisors.

• Edgewise bracket was bonded 1 mm gingival to the centre of the crown of upper and lower incisors to extrude them and to reduce anterior open bite.

• Initial leveling and alignment was done with the use of 0.014 ss multiloop arch wires.

• Upper spacing were closed by power chains with 0.016 ss round wire.

• Upper arch contraction was done by 0.016x 0.022 inch rectangular ss arch wires with tear drop contraction loops .

• At the end of treatment, elastics was used for better interdigitation.

Fig: Initial leveling and alignment by 0.014 ss round wire with multi-loop.

Fig: closing space between central incisors by 0.016 ss round wire with power chain.

Fig: Arch contraction – right side

Fig: Arch contraction by .016*.022 ss rectangular wire with tear drop loop.

Pre-treatment Post-treatment

DISCUSSION AND RESULTS:

• Total treatment time was 24 months.• The result was slightly compromised in that there

on right side, canine relationship was not class I and lip procumbancy was not fully corrected as because the patient refused to extract teeth.

• However, the patient was happy with his appearance and reduced lip incompetency.

Cephalometric measurement before and after —

Variables Before treatment Clinical norms After treatment

SNA 79.1° 80.0..89.0° 78.2°

SNB 72.1° 75.0..82.0° 71.5°

ANB 7.0° 2.0..4.0° 6.7°

SND 69.0° 76.0..77.0° 68.8°

IIA 96.6° 130.0..150.0° 121.2°

SN-OcP 21.4° 14.0° 23.7°

SN-GoGn 46.4° 30.0° 47.8°

Max1-NA 33.5° 22.0° 16.3°

Max1-SN 112.7° 108.0° 94.5°

Mand1-NB 42.9° 25.0° 35.9°

1u-NA 6mm 4mm 4mm

1l-NB 6mm 4mm 7mm

Holdaway Ratio 8mm 0..2mm 0mm

S-L 14mm 51mm 7mm

S-E 11mm 22mm 14mm

——— Initial ——— Post Treatment

Cephalometric superimposition

Cephalometric radiography superimposition comparing before and after showed that the open bite problem was corrected by---•The upper incisors tipped backward and retracted•The lower incisors extruded due to positioning of brackets 1 mm gingival to the centre of the crown.•Upper and lower molars were not extruded; Extrusion of molars are not advisable in open bite cases as because of relapse tendency.

Dental Maxilla Soft Tissue Profile

SEGMENTAL SUPERIMPOSITION

Upper Lip Drape

At the end of treatment---• Facial photographs

show an improved profile.

• Lip procumbency was reduced.

At the end of treatment---• Ideal overjet and

overbite were achieved.

At the end of treatment---• Proper alignment and

nice gingival contour were attained.

Tooth loss due to periodontal disease--• When a tooth lost due to periodontal disease, that space is

very difficult to close.• As a general rule, it is better to move teeth away from such

an area, in preparation for a prosthetic replacement, because of the risk that normal bone formation will not occur as the tooth moves into the defect.

• In older pt who has lost a tooth due to periodontal disease, it is not a good judgment to attempt to close the space.

--------PROFFIT

• It is important to explore and understand various aspects of orthodontic treatment where adults need special considerations in contrast to adolescents.

• Adult orthodontics is basically same as adolescent orthodontics for tissue changes associated with tooth movement, stages of treatment and goal of treatment.

• But there are certain differences in several aspects namely psychosocial, biological and mechanical aspects where adults need special consideration for behavioral and clinical management

Psychosocial factors• Adult patients have high treatment expectations.• They are more serious about the detail of the treatment as treatment time,

complexity of treatment, number of visits, likelihood of correction etc. • They have been shown to have more discomfort from appliances. • They are more co-operative in following the instructions from orthodontists

such as elastic wear, hygiene maintenance, keeping their appointments etc. but they don’t commit to long-term treatment .

• In other words, adults demand best treatment results in a short time. • Therefore, it is quite important to apprise these patients about the limitations &

complexity of the treatment, increased treatment time & high relapse potential.• Adult patients may have hesitation in accepting visibility of orthodontic

appliances. They may demand esthetic appliance e.g. esthetic brackets, lingual appliance, invisalign etc irrespective of their limitations .

Periodontal susceptibility

• Adolescents more resistant to bone loss as a result of periodontal disease but highly susceptible to gingival inflammation.

• Adults Higher degree of susceptibility to bone loss as a result of periodontal disease.

The bone level

• The minimum amount of bone support necessary for teeth to withstand orthodontic forces in a plaque-controlled environment has yet not been established. Reduced bone support is not a contraindication to orthodontic therapy.

• The ideal alveolar bone for closing first molar space is 6 mm in mesio-distal direction and 7 mm in bucco-lingual direction. If the pt does not fit these characteristics, one can start guided bone regeneration technique, which is widely used for orthodontic movement in areas with bone defects.

CONSIDERATIONS REGARDING EXTRACTION

• Extraction choice may be affected by periorestorative status of dentition or already extracted tooth complicating the treatment plan.

• In adults, closing an old extraction site is difficult. When there is a dense cortical layer of bone formed within the alveolar process of a previously (long ago) extrated tooth, it become very difficult to close the space.

• Tooth movement is slowed to a minimal when the root encounters cortical bone along the resorbed side of alveolar ridge.

• Tooth movement is also greatly slowed & root resorption more likely when a tooth is faced against a cortical plate.

• Maintenance of closed spaces is also very difficult (difficult to close and keep it closed).

• It may need uprighting to open the space mesially to receive prosthesis rather than attempting space closure.

• Existing occlusion is maintained when occlusal difficulties are not present. Lower incisor extraction & proximal stripping are preferred over bicuspid extraction to relieve crowding.

CONSIDERATIONS REGARDING APPLIANCE PLACEMENT

• While bonding, special considerations may be required due to presence of restorations such as porcelain and metallic surfaces.

BIOMECHANICAL CONSIDERATIONSAdult bone is less reactive to mechanical forces .Loss of attachment leads to apical shift of centre of resistance, thereby increasing distance from centre of resistance to point of force application in turn leading to increased tipping moment produced by the given force.Therefore greater countervailing moment is required to balance this greater tipping moment to translate periodontally compromised tooth .

When bone has been lost, same amount of force produces greater pressure in PDL of a compromised tooth than a normally supported one.

Considerations Regarding Tooth movements

• To correct deep bite in young patients, posterior extrusion is allowed because of compensation made by vertical growth. But overbite correction in adults should be carried out by intrusion of anterior teeth, not by extrusion of posterior teeth.

• Palatal expansion is carefully done to avoid buccal tipping due to extrusion associated with it.

• Most mechanotherapy has extrusive component. Retraction force has a larger extrusive force component if the bone loss is most pronounced. Hence, light continuous intrusive force should be maintained during retraction.

• In adult patients, segmented arch mechanics is preferred because light force is required for adults.

CONSIDERATIONS REGARDING VULNERABILITY TO ROOT RESORPTION

• Adult patients must be informed about the risk of root resorption and thoroughly evaluated for the susceptibility to root resorption . All measures should be taken to manage root resorption.

CONSIDERATIONS REGARDINGVULNERABILITY TO TMD

• There is a higher risk of developing TMD in adults than adolescents, which may not be related to orthodontic treatment.

• Hence, adult patients need a thorough check up for the signs of TMD before initiation of orthodontic treatment.

CONSIDERATIONS REGARDING TREATMENT TIME

• Tissue remodeling associated with tooth movement is slow leading to slow rate of tooth movement making the treatment time longer.

• Activation in adults usually in 50’s and onwards is required to be done after longer period i.e. 3-6 weeks as against 2-4 weeks required in adolescents.

• Initiation of tooth movement takes longer time as compared to adolescents. The delayed response to mechanical stimulus, is suggested to be caused by insufficient source of preosteoblasts as a result of reduced vascularization with increasing age.

• After delayed initial tissue reaction, rate of tooth movement in adults is not that much different as compared to that in adolescents.

2 years after treatment (Follow up)

Immediately after treatment 2 years after treatment

Open bite

Health & Medicine

Transcript of Open bite