Orthodontic correction of occlusal plane canting part 1
- 1. Faculty of Dentistry Mansoura Egypt Dr Maher Fouda Professor of orthodontics Orthodontic correction of occlusal-plane canting Part 1
- 2. Occlusal-plane canting is a challenging problem for orthodontists because it cannot be solved easily without surgical intervention. Normally, a LeFort I osteotomy and concomitant mandibular surgery is used to correct the problem, even in patients with mild facial asymmetry but with noticeable occlusal-plane canting. Patients illustrating a maxillary cant with the use of a tongue spatula.
- 3. The cant of the occlusal plane in the frontal plane can be the result of skeletal asymmetry of the jaw bones or the asymmetric vertical position of anterior or posterior teeth. Before the advent of skeletal anchorage in orthodontics, the correction of occlusal-plane canting had only limited indications, whether the origin was skeletal or dental. Therefore, surgery was considered the only method for correcting this problem. However, skeletal anchorage has made possible true intrusion of molars, which was difficult with conventional orthodontic means. Moreover, it is now possible to correct occlusal-plane canting by controlling the vertical position of the molars
- 4. A , The pupillary and ear planes can usually be used as horizontal references. A perpendicular plane through nasion can be helpful in assessing the left-to-right facial asymmetry. The asymmetry is usually the least at the cranial base area and the greatest at the mandible and chin area, as seen in this 45-year-old woman with a right mandibular condylar osteochondroma. B , Evaluate the smile. This may emphasize the asymmetry. PP , Pupillary plane; EP , ear plane; Com , commissure plane; OP , occlusal plane; IB , inferior border of mandible; FM , facial midline plane; CM , chin midline. C , The profile view is helpful to determine AP and vertical facial balance. CFH , Clinical Frankfort horizontal plane; SNP , subnasale perpendicular plane. D , A tongue blade placed transversely across the occlusion demonstrates the vertical asymmetry and cant in the occlusal plane. E , The occlusion is evaluated for vertical, transverse and AP asymmetry including midlines, cross-bites, occlusal cant, open bites, yaw, and so on. UIM , Upper incisor midline; LIM , lower incisor midline Diagnosis of occlusal canting in facial asymmetry
- 5. It was reported that all people have some craniofacial asymmetry, even in esthetically normal or pleasing faces. In addition, an occlusal cant in most normal patients might be too small to detect. Patients often recognize their occlusal canting as being unpleasant esthetically when there is a discrepancy in parallelism between the lip line and the occlusal plane (a) Significant asymmetry of the lower face, with the mandible and chin point to the patients left, and transverse cant of the rima oris (opening of the mouth) (left and right commissures at different vertical levels) and the inferior chin plane. (b) Transverse cant of the maxillary occlusal plane evident, canted down on the patient’s right. (c) Inferior view highlights asymmetry of the chin and lower lip in relation to the upper lip. (d) Dental mirror handle held against the maxillary dentition demonstrates a transverse cant in relation to the interpupillary plane. Diagnosis of occlusal canting in facial asymmetry
- 6. Measurement of occlusal cant in the maxilla. A, The magnitude of occlusal cant by measuring the degree of canting relative to the true horizontal. The reference lines for determining the cant are as follows: a true horizontal represented by a tangent to the normal supraorbital rims (1) and a vertical line drawn through the crista galli and upper third of the nasal septum (2). The degree of cant is determined with respect to the true horizontal. On this AP cephalogram, the degree of canting of the occlusal plane was 6 degrees. B, The magnitude of occlusal cant can be measured by evaluating the medial canthus-canine distance. In the patient above, the medial canthus to right canine distance was 62 mm; the distance to the left canine was 56 mm, for a total vertical discrepancy of 6 mm. Padwa et al reported that 4° is the threshold for recognizing an occlusal cant. However, they measured occlusal-plane canting from a horizontal line connecting the supraorbital rim. Diagnosis of occlusal canting in facial asymmetry
- 7. In some patients with vertical asymmetry of the right and left posterior teeth without anterior occlusal-plane canting, the occlusal canting becomes obvious after orthodontic leveling. Facial asymmetry that is too minimal for orthognathic surgery but accompanies recognizable occlusal canting can be corrected by skeletal anchorage-reinforced orthodontic treatment. However, few biomechanical systems use skeletal anchorage to correct occlusal canting.
- 8. Fushima et al. (1989) examined the vertical height of right and left posterior teeth in cases with mandibular asymmetry by the use of P-A cephalograms, and revealed that the vertical height of posterior teeth on the suppressed side of the mandible was lower than contralateral teeth. These findings suggest that occlusal deviations are related to facial growth.
- 9. In orthodontic diagnosis, the occlusal plane represented by a line drawn from the midpoint of the upper and lower central incisor edges to the occlusal surface of the upper and lower first molars on the lateral cephalogram should be carefully evaluated. The cant of the occlusal plane must relate to the sagittal inclination of the condylar path and the guidance of lingual concavity of the upper incisor (Dawson, 1989).
- 10. Sagittal condylar inclination is defined as the angle between the protrusive path of the condyle and usually the Frankfort horizontal, or any other horizontal reference plane, such as in the current study’s Camper’s plane. Camper’s Plane •“A plane established by the inferior border of the right or left ala of the nose and the superior border of tragus of both ears” •
- 11. Transverse canting of the maxillary occlusal plane should be assessed visually in frontal view with the aid of (a) photographic retractor sand /or (b)orthodontic cheek retractors,and(c) with placement of a wooden tongue spatula(or dental mirror handle)on the occlusal plane .
- 12. (a) Frontal view photograph showing assessment of cant of occlusal plane in relation to interpupillary plane. (b) Frontal view photograph showing true facial midline for documenting facial asymmetry with deviation of mandible toward left side. (c) Frontal view photograph illustrating cant of lower border of mandible. (d) Submental view photograph documenting mandibular asymmetry. (e) Superior (Bird’s eye) view photograph.
- 13. UNILATERAL INTRUSION (VERTICAL ASYMMETRY CORRECTION) Clinical objective • Asymmetrical intrusion of the maxillary or mandibular teeth to level the occlusal plane and smile line. Skeletal anchorage can be used in patients with occlusal canting to reduce the need for orthognathic surgery.
- 14. Treatment options • Unilateral mini-implant intrusion, except where contra-indicated in patients with a Class III skeletal pattern or reduced lower anterior face height. • Conventional anchorage involving asymmetric headgear. • Hybrid functional (orthopaedic) appliance, but with a reliance on asymmetric extrusive changes. • Asymmetrical orthognathic surgical movements. ACTIVATOR HEADGEAR
- 15. Relevant clinical details • Unilateral or even bilateral asymmetric intrusion is ideal for those patients with a predominantly vertical asymmetry accompanied by an average or increased maxillo-mandibular angle and Class II features. Full bilateral treatment involves intrusion of teeth in diagonally opposing quadrants (e.g. upper right and lower left quadrants). Class II malocclusion with accentuated occlusal plane inclination corrected with miniplate: a case report Dental Press J Orthod. 2016 May-June;21(3):94-103
- 16. Relevant clinical details • The incisor relationship (overjet, overbite). • The maxillary and mandibular occlusal planes and whether an occlusal cant is present. • The upper incisors’ vertical display (on both passive and smiling exposure) and the smile arc.
- 17. Biomechanical principles • Simultaneous buccal and palatal mini-implant anchorage in the maxillary arch ensures true vertical movements within a quadrant, and avoids transverse side-effects or the need for a modified TPA (which allows differential molar movements). Since lingual insertion sites have a low success rate then mandibular intrusion utilises buccal mini-implants only and requires transverse control using a full fixed appliance.
- 18. • The mini-implants should be vertically positioned in relatively apical sites, such that the buccal one is Biomechanical principles close to, or at the, muco-gingival junction. This provides an adequate distance for effective traction, especially as the adjacent teeth intrude towards the implant head. • Unilateral intrusion forces should be applied with a rigid (0.019 × 0.025) steel archwire in place.
- 19. Simultaneous buccal and palatal mini-implant anchorage in the maxillary arch ensures true vertical movements within a quadrant, and avoids transverse side-effects.
- 20. Clinical tips and technicalities • Consider removal of erupted third molars (prior to orthodontics) in the quadrant(s) where molar intrusion is required. • Bond the second molars, where erupted, in the quadrant requiring intrusion. • In vertical correction cases, monitor the occlusal plane by measuring the overbite involving the incisors and canine teeth, and their vertical display relative to the lip level. Also, monitor lateral openbites and hence the need for extrusion of the opposing teeth or additional intrusion in the diagonally opposite quadrant.
- 21. Mid-treatment problems and solutions • Vertical side-effects such as a rollercoaster buckling of the arch and lateral openbite: Ensure that the second molars are bonded when fully erupted. Avoid the application of traction with a flexible archwire in situ. Vertical settling elastics may be used to close a lateral openbite by extrusion of the opposing arch. The elastics may be connected either to the mini-implant anchored teeth or directly to the mini-implant head. The latter avoids any risk of extrusive relapse of the intruded teeth.
- 22. The roller coaster effect is observed when a wire of low strength such as NiTi is used for canine retraction NiTi deos not have the strength to remain rigid when a retracting force such as an elastic chain is stretched from the molar to the canine. The molar and premolar crowns tend to tip mesially and extrude distally. The flexible Niti then bends gingivally and as a result tends to tip the canine crown distally . The orientation of the canine bracket when the crowns tips distally tends to extrude the incisors and deepen the bite In short ,the canine occlusal plane goes for a toss and when we follow the occlusal plane from the right molar to the left molar it resembles a roller coaster and hence the name is used
- 23. Clinical steps for unilateral intrusion Pre-insertion 1. Determine the insertion sites, e.g. a buccal one between the maxillary premolars and a palatal one between the molars, prior to bond-up. The insertion of both buccal and palatal mini-implants in the same interproximal space should be avoided. Instead, the palatal mini-implant should be in a more distal site than the buccal one, since more molar interproximal space is available on the palatal aspect. 2. This pre-planning enables active divergence of adjacent premolar roots to be undertaken, to allow for both ease of buccal mini-implant insertion and subsequent vertical tooth movements. For example, diverge the premolar roots by adding mesial and distal tip to the first and second premolar brackets, respectively. Remember that these tip alterations can readily be corrected at the treatment finishing stage.
- 24. Insertion timing Determine this relative to the fixed appliance bond-up, by deciding how much arch alignment is appropriate before mini-implant insertion. Crucially, if there is insufficient interproximal space at the planned insertion site then consider a preliminary phase of fixed appliance treatment in order to diverge the roots and hence facilitate mini-implant insertion . This is achieved by bonding the bracket(s) with a modified tip, especially adding mesial tip to the normal second premolar bracket orientation . Indeed, I routinely perform this step prior to the majority of buccal insertions since it is a simple process which can make mini-implant treatment much easier. The bracket position is then corrected during the fixed appliance finishing stage (after explantation). Furthermore, it may be biomechanically beneficial to align the full arch such that it is ready to accommodate a rigid (e.g. 0.019 × 0.025 stainless steel) archwire and powerarm by the time of mini-implant insertion. This helps with sliding mechanics and the reduction of unfavourable vertical side-effects.
- 25. (a) A pre-treatment panoramic, and (b) pre-insertion and (c) post-insertion intra-oral radiographs. The insertion site between the left maxillary second premolar and first molar roots is highlighted in red in images (a) and (b). Root divergence has been performed to widen the interproximal space before radiograph (b) was taken Diagrams of the premolar and first molar teeth where (a) the second premolar bracket has been bonded with mesial tip to cause (b) mesial tipping of this root during the fixed appliance alignment phase and hence an increase in this interproximal space
- 26. Clinical steps for unilateral intrusion Pre-insertion 3. Align and level the whole arch or initially only the segment(s) due for intrusion. This depends on whether there is a vertical discrepancy between the anterior and posterior teeth, where a large step favours segmental mechanics; whilst the risk of occlusal interferences from displaced anterior teeth necessitates full arch alignment. 4. Expand the maxillary arch where necessary to facilitate arch coordination (following subsequent mandibular autorotation).
- 27. Clinical steps for unilateral intrusion Pre-insertion 5. Include bonded tubes on the second molars, if fully erupted, early in treatment. If the second molars are not fully erupted then do not bond them during initial alignment. Remember to avoid molar bands in order to facilitate effective gingival hygiene at the posterior limit of the dental arch where a reduction in crown height may occur and toothbrush access is most limited. 6. Once a 0.019 × 0.025 NiTi archwire has been inserted then book two clinical appointments if a stent is to be fabricated (which is especially valuable for palatal site guidance).
- 28. Clinical steps for unilateral intrusion Pre-insertion 7. At the preparatory appointment take an alginate impression for a guidance stent if desired. Palatal stents do not require an accurate buccal alveolar impression, but remember not to wax out the brackets adjacent to a buccal insertion site. 8. Take periapical radiographs or a sectional CBCT to evaluate the positions of the roots adjacent to the insertion sites, either at the preparatory stage (when stent usage is planned) or at the start of the insertion appointment. E) implantation planning on maxilla, (A) 3D-image reconstruction of the dentition, (B) virtual implant planning in Simplant software, The surgical stents fabricated by the SurgiGuide System.
- 29. Mini-implant selection 9. Maxilla: use 1.5 mm diameter, 9 mm length mini-implants (for Infinitas), with short and long necks on the buccal and palatal alveolar sides, respectively. However, if the palatal tissues are particularly thick or the patient is still undergoing considerable somatic growth, then a 2 mm diameter version may be indicated to give maximum primary stability without relying on full depth intra-bony insertion. 10. Mandible: body length selection depends on the anticipated cortical depth and density such that a long length (9 mm) version is preferable for adolescent patients, where the cortical bone is immature. An Infinitas 1.5 mm diameter, 6 mm length, short neck version may be used in an adult.
- 30. Insertion 11. Superficial anaesthesia of the insertion sites, e.g. blanch the overlying mucosal area with a local anaesthetic injection, especially in the palatal site, although topical anaesthetic alone may be sufficient in the buccal site. 12. Fit the stent (where applicable). 13. Use a mucosal punch for palatal insertions. Temporarily remove any stent, after the surface has been marked with it in situ, so that the mucotome can be applied perpendicular to the surface, providing a clean cut of the tissue. If necessary, then remove the mucosal tissue with a mosquito forceps and/or Mitchell’s trimmer.
- 31. 14. In adults, use a cortical bone punch to perforate the relatively dense thick palatal and mandibular cortex. 15. Insert buccal and palatal maxillary, and buccal mandibular mini- implants, according to the treatment plan. Remember to use a speed-reducing (e.g. 128:1 ratio) contra-angle handpiece at less than 100 rpm for palatal sites. 16. The buccal insertion sites should be at or close to the muco- gingival junction and the vertical angle of insertion should be perpendicular to the bone. These details enable reliable attachment of the traction and a maximum range of intrusion movement. cortical bone punch speed-reducing (e.g. 128:1 ratio) contra-angle
- 32. 17. Take an intra-oral radiograph if close root proximity is clinically suspected (due to pain sensation on percussion of an adjacent tooth). 18. Complete insertion to the point that the mini-implant neck is partially submerged but the head is fully accessible.
- 33. Post-insertion 19. Insert a 0.019 × 0.025 steel archwire. 20. Bond attachments (buttons or cleats) to the palatal surfaces of the crowns adjacent to any palatal mini-implants. 21. Apply approximately 50 g (elastomeric chain) traction for the first four to six weeks. This utilises the palatal attachments and the simplest configuration is a ‘V’ one, where the traction component’s ends are attached to the teeth and its mid-section engages the mini-implant head.
- 34. On the buccal side, the traction may be applied directly to the adjacent brackets or around the archwire. Following the initial healing period, stronger (150–200 g) elastomeric or closing coil auxiliary traction should be used.
- 35. 22. Monitor treatment progress by recording the following features at the start of intrusion and at subsequent appointments: overjet, AOB/overbite, canine relationship, the upper incisor display (at rest and on full smiling), occlusal cant and presence of any molar openbite. 23. Monitor the periodontal condition (probing depth) of the terminal molars.
- 36. 24. Consider over-correction of the intrusion changes to allow for possible relapse and/or keep the miniimplants in situ until it is clear that further anchorage is not required. 25. Consider an initially intensive retention regimen, e.g. three months full-time wear of plastic retainers with whole arch occlusal coverage. These should prevent early molar extrusion after debond.
- 37. UNILATERAL INTRUSION EXAMPLE • A 28 year old female presenting with a Class II division 2 malocclusion on a skeletal I base with an average MMPA . She had predominantly vertical dentofacial asymmetry with the maxillary plane canted downwards on the left side and more gingival display on this side on full smiling (although she camouflaged this by habitually smiling by only a limited extent). All first premolars plus a lower incisor were absent, and unsuccessful surgical recontouring of the maxillary gingival margin had previously been performed. ( a–c) Pre-treatment views where the patient’s habitual smile camouflages her vertical maxillary cant and gingival level asymmetry. The Class II division 2 malocclusion is shown with absence of upper first premolars and a lower incisor
- 38. UNILATERAL INTRUSION EXAMPLE The maxillary arch was levelled and aligned to accommodate a 0.019 × 0.025 steel archwire. d–h) Left-sided intrusion commences with a 0.019 × 0.025 steel archwire in situ. Elastomeric traction is applied to the brackets and palatal cleats from mini-implants sited buccal and mesial to the maxillary left first molar, and palatal and distal to this first molar
- 39. A 1.5 diameter, 9 mm length mini-implant was then inserted on both sides of the left maxillary alveolus: mesio-buccal and disto-palatal to the first molar (Figs 10.3f–h). Elastomeric traction was applied buccally to the upper left premolar bracket and molar tube, and palatally to buttons on the palatal surfaces of the molars.
- 40. Both the malocclusion and smile aesthetics were improved by five months of intrusion prior to bonding the lower fixed appliance . Notably there was more vertical clearance for the left molars, although it appeared that these may have undergone some compensatory eruption. (i–k) the maxillary cant is levelling and the lower arch is being aligned, with relatively gingival bracket positions in the lower left quadrant to assist with vertical compensation and overbite reduction.
- 41. After a further four months the maxillary and mandibular planes and smile line were level . Intrusion was continued for some over-correction and any consequent left lateral openbite would be corrected by lower left molar elastic extrusion (given the originally deep overbite).
- 42. CENTRELINE CORRECTION EXAMPLE This 27 year old female presented with a Class II division 2 malocclusion on a mild skeletal II base. She had transverse skeletal asymmetry with the chin point displaced to the left side (without a functional displacement) and a subtle degree of vertical asymmetry (occlusal cant slightly higher on the left side).
- 43. The upper incisor–lip relationship was aesthetically satisfactory. The upper right canine and the first premolars from the other three quadrants were absent. The upper and lower dental centrelines were displaced to the right and left sides, respectively, and the buccal segments exhibited similar asymmetry, including a ¾ unit Class II relationship of the left canines. (a–d) Pre-treatment views showing this Class II malocclusion with absence of the upper right canine and first premolars in the other three quadrants, asymmetric buccal segment relationships and centreline discrepancies
- 44. CENTRELINE CORRECTION EXAMPLE Both arches were initially levelled and aligned. The left Class II canine relationship, deep overbite and lower centreline problems were additionally corrected by the use of pushcoil to re-open the lower left first premolar space. (e–g) The lower left premolar space has re-opened during alignment and lower centreline correction. Upper posterior and lower anterior miniimplants are being used for upper centreline correction and lower molar protraction, respectively. Indirect anchorage is used to provide a horizontal vector of traction from a 0.019 × 0.025 steel auxiliary wire (connected vertically between the archwire and mini-implant head).
- 45. This was followed by asymmetrical traction, predominantly Class III elastics on the right side, although a small residual centreline discrepancy was accepted due to tooth size discrepancies . Debond views
- 46. Use of rhythmic wire system with miniscrews to correct occlusal-plane canting Yoon-Goo Kang, Jong-Hyun Nam, and Young- Guk Park Seoul, Korea American Journal of Orthodontics and Dentofacial Orthopedics Kang, Nam, and Park 541 Volume 137, Number 4
- 47. A biomechanical system was developed called “rhythmic wire,” which consists of 2 miniscrews (on the maxillary and mandibular teeth), intrusion wire, extrusion wire, transpalatal arch, and lingual arch. This report presents the use of this method in 2 patients for correcting the occlusal cant to avoid or minimize orthognathic surgery
- 48. Rhythmic wire Rhythmic wire was initially developed to control the vertical position of the posterior teeth and consists of intrusion rhythmic wire and corresponding extrusion rhythmic wire. In addition, a transpalatal arch or a lingual arch can be applied if there is a need to control the third-order torque of posterior teeth that face an intrusion or extrusion force. Rhythmic wire can also be a good option for patients with palatally or lingually tipped posterior teeth because buccal tipping of the teeth can occur without a transpalatal or lingual arch. Intrusion rhythmic wire: upper, schematic diagram of the intrusion rhythmic wire; lower, after placemen
- 49. The intrusion wire is formed with 0.019 × 0.025-in beta-titanium alloy straight wire of appropriate length (usually the length between the first premolar and the second molar) with hooks on each end for engagement to the main archwire Intrusion rhythmic wire: upper, schematic diagram of the intrusion rhythmic wire; lower, after placemen
- 50. If a decrease in the intrusion force is required, the size of wire can be reduced, or helices can be included. There is no consensus on the optimal force for the intrusion of teeth, but there appears to be some accord between researchers that posterior teeth require more force than anterior teeth. Kalra et al used 90 g of force per posterior tooth, Park et al suggested 150 to 200 g, Umemori et al recommended 500 g, and Melsen and Fiorelli used 50 g buccolingually per posterior tooth. The intrusion wire is placed on the vestibular side of the miniscrew, which is generally placed between the second premolar and the first molar, and each end is activated to engage the main archwire . Intrusion rhythmic wire: upper, schematic diagram of the intrusion rhythmic wire; lower, after placemen
- 51. The point where the hooks of the intrusion rhythmic wire engage depend on the clinical need; this means that the clinician can choose the site to apply the force and change the site by adjusting the intrusion wire without replacing the miniscrew. The miniscrew should have an undercut in its head design to place the intrusion wire, and an elastomeric ring can be used to secure the intrusion wire to the miniscrew. Intrusion rhythmic wire: upper, schematic diagram of the intrusion rhythmic wire; lower, after placemen
- 52. The extrusion rhythmic wire, which is placed on the opposite dentition, is made from stainless steel wire (or cobalt-chromium wire with heat treatment) in a clover-like form . An indentation is prepared on the top half circle (vestibular side) to accept the miniscrew head, and each root (occlusal side) has a hook for attachment to the main archwire. configuration and activation Extrusion rhythmic wire: upper, schematic diagram of the extrusion rhythmic wire; lower, after placement Clover Plants
- 53. Activation is achieved by manipulation of the horizontal loops. A smaller force than for intrusion is sufficient for extrusion of the teeth. However, to prevent deformation of the wire, its size should be greater than 0.016 in, and stainless steel wire is recommended. Helices or loops can be added to reduce the force .
- 54. Modifications of the rhythmic wire: left, a helix was included in the intrusion wire to reduce the force; right, loops were added to the extrusion wire to reduce the force The intrusion and extrusion rhythmic wires should be used simultaneously to maintain the integrity of the occlusal contacts. In addition, the position of the hooks is determined by the clinical situation
- 55. The extrusion or intrusion of molars from the buccal side can cause buccal or lingual crown tipping, which is generally undesirable. To minimize this tipping, a transpalatal or lingual arch can be applied with a rectangular lingual sheath to the active (extrusion or intrusion) side, and a round sheath can be applied to the other side, as described by Rebellato. Also, full alignment, leveling, and space consolidation are recommended before applying a rhythmic wire, and the main archwire should be rectangular stainless steel for more predictable and easy control of the posterior quadrant
- 56. Patient 1 A 20-year-old woman was referred from a local dental clinic complaining of masticatory problems on the left side. The intraoral features showed moderate crowding of her maxillary dentition, an anterior edge-to-edge bite, and a posterior crossbite on the left side . The occlusal relationship was Class II molar and Class I canine on her right side, and Class III molar and canine on her left side . Her maxillary right posterior teeth were positioned vertically low compared with the left side . After reviewing her condition, she was diagnosed with skeletal Class III facial asymmetry and a canted posterior occlusal plane.
- 57. Her skeletal problems were mild, and she did not require facial changes. She refused surgery and also declined treatment accompanying the extraction of her premolars. The treatment plan was established to distalize the maxillary right posterior and mandibular left posterior teeth with miniscrews to resolve the crowding and correct the occlusal relationships with rhythmic wire upper row, pretreatment study model. Note the difference in the vertical heights of the molars between the left and right sides; middle and lower rows, application of the rhythmic wire system
- 58. After distalization of the molars, aligning and leveling were performed. The leveling procedure unmasked the posterior occlusal canting and showed an apparent difference in the gingivae between the left and right sides while smiling . It was decided to intrude the maxillary right posterior teeth because of the excessive gingival display on the right side. Miniscrews were placed between the maxillary right second premolar and molar, and between the mandibular right second premolar and molar. An intrusion rhythmic wire was placed on the maxillary right posterior teeth, and an extrusion wire was placed on the mandibular right posterior teeth. In addition, a transpalatal arch and a lingual arch with a rectangular lingual sheath were applied on the right side, and a round sheath was used on the left to control the inclination of the teeth
- 59. The occlusal cant was corrected by the intrusion of the maxillary right posterior teeth. Finishing and detailing of the occlusion was then performed, and the intruded maxillary right posterior teeth were maintained with wire ligation to the miniscrew. After removing the appliances, a canine-to- canine lingual bonded retainer was placed in the maxilla, and a wraparound retainer was used for the mandible. Superimposition of pretreatment and posttreatment lateral cephalogms showed reductions of the difference in vertical height of the right and left molars . Pretreatment and posttreatment cephalograms and superimposed tracings of patient 1: black line, pretreatment; red line, posttreatment. The difference in vertical height of the molars was reduced mainly by intrusion without remarkable changes in the mandibular position
- 60. Distalization of the molars and leveling took 15 months, correction of the occlusal cant with rhythmic wires took 9 months, and finishing took 4 months. Overall, the total active treatment period was 28 months
- 61. PATIENT 2 A22-year-old womanvisited the orthodontic department of Kyunghee University complaining of crowding of her maxillary teeth and protrusion of her lips. The intraoral examination showed maxillary and mandibular anterior crowding, and the facial examination showed a canted occlusal plane with asymmetric elevation of the right and left corners of the mouth during smiling that exaggerated the occlusal canting (Figs 7 and 8).
- 62. upper row, pretreatment study model; middle and lower rows, application of the rhythmic wire system. The treatment plan was to extract the first premolars to resolve the crowding and lip protrusion and to apply rhythmic wire to correct the occlusal canting.
- 63. After the conventional aligning and leveling, and closure of the extraction site with retraction of the anterior teeth, rhythmic wire was applied to the right side of her dentition. The application side was determined by the amount of gingiva showing.Her occlusal canting was corrected after 4 months of rhythmic wire application.
- 64. As with patient 1, a canine-to-canine lingual bonded retainer was placed on themandibular dentition, and awraparound retainer was used for the maxillary dentition. The total treatment duration was 18 months, which included 12 months for aligning, leveling, and anterior retraction; 4 months for correcting the canting; and 2months for detailing. Smile photos of patient 2. From left, pretreatment, midtreatment, and after rhythmic wire application. Occlusal canting before treatment was corrected.
- 65. Superimposition of pretreatment and posttreatment lateral cephalograms showed reduction of the difference in vertical height of right and left molars .
- 66. RESEARCH AND REVIEWS: JOURNAL OF DENTAL SCIENCES Miniscrews: Clinical Application of Orthodontic. Abu-Hussein Muhamad, and Watted Nezar. RRJDS | Volume 2 | Issue 3 | July - September, 2014
- 67. Miniscrew-assisted multidisciplinary orthodontic treatment with surgical mandibular advancement and genioplasty in a brachyfacial Class II patient with mandibular asymmetry Vanessa Paredes-Gallardo, Veronica Garcıa-Sanz, and Carlos Bellot-Arcıs Valencia, Spain November 2017 Vol 152 Issue 5 American Journal of Orthodontics and Dentofacial Orthopedics After periodontal treatment, miniscrews were placed to correct the occlusal plane canting and the excessive curve of Spee with orthodontic treatment. The surgical treatment plan consisted of a bilateral asymmetric sagittal split osteotomy for mandibular advancement and genioplasty.
- 68. Clinical applications of the Mini-Screw-Anchorage-System (M.A.S.) in the maxillary alveolar bone Aldo Carano, Stefano Velo, Cristina Incorvati, Paola Poggio* PROGRESS in ORTHODONTICS 2004; 5(2): 212-230
- 69. The correction of a canted occlusal plane is easily obtained with the mini-screws as skeletal anchorage. The miniscrew is used as anchorage to intrude the extruded canines and the laterals on the side of the cant. In this case the screw was centered between the roots of the maxillary canine and first premolar (a). After correction of the occlusal plane and of the dental midline (b). The correction of a canted occlusal plane is often considered an impossible objective with traditional orthodontic mechanics. With the mini-screws as skeletal anchorage this objective can be achieved more predictably.
- 70. mini-screws are placed in between the upper laterals and the canines or in between the upper canines and the bicuspids for the maxillary arch and in between the laterals and the canines for the mandibular arch.
- 71. The miniscrew is used as anchorage to intrude the extruded canines and the laterals on the side of the cant, and to center the dental midline. During the intrusive movements, it is very important to center the mini-screws in between the roots of the teeth that need to be intruded in order to avoid the interferences between the teeth and the screw.
- 72. Iatrogenic Sequela of Orthodontic Treatment Katja Kritzler, DDS, postgraduate student 1 Ulrich Kritzler, DDS, Dr. med. dent., FZA für Kieferorthopنdie 1 1 Private practice of orthodontics, Münsterstr. 25, D-48231 Warendorf, Germany Working Paper · December 2015 DOI: 10.13140/RG.2.1.2709.7688/2 Side effect of indiscriminate levelling of the upper arch: development of a canted plane of occlusion.
- 73. The class II elastics that are often used to correct a class II malocclusion, so-called class II mechanics, could cause the downward and backward rotation of the OP due to mandibular molar extrusion and maxillary incisor extrusion , consequently, increased the angle of the OP with SN plane. Zimmer et al. also observed several significant changes in the occlusal plane inclination due to oppositely guided intermaxillary elastics, the induced shift with class II elastics was clockwise, while class III elastics was counterclockwise. Progress in Orthodontics 2014, 15:41 Changes of occlusal plane inclination after orthodontic treatment in different dentoskeletal frames Jin-le Li Chung How Kau and Min Wang
- 74. According to Burstone and Choy unwanted side effects will occur when a continuous NiTi arch is used in a unilateral or bilateral high canine case. They pointed out that the canine will be extruded but the posterior adjacent teeth will be intruded and tip mesially and the anterior adjacent teeth will be intruded and tip distally. They concluded that the intrusive force on the premolar will finally produce a large counterclockwise rotation on the ipsilateral molar which will tip the posterior teeth mesially. A) Straight wire mechanics used for canine extrusion. B) Note the side effects on the lateral incisor and first premolar, which made the conditions of the case worse.
- 75. Traction of tooth with self-ligating brackets. A) With NiTi archwire attached to all teeth. Deleterious effects on adjacent teeth (intrusion and buccal inclination, especially in the lateral incisor); B) procedure carried out to minimize deleterious effects on adjacent teeth supported by an rigid arch (the intrusive effects on adjacent teeth exist, but do not result in effect on the teeth due to the use of the rigid arch).
- 76. After consistent alignment of the brackets and teeth is accomplished, a straight 0.019 x 0.025-inch stainless steel rectangular wire should be fitted into all brackets except the canine bracket. The heavy ground arch will be bypassing the high canine which is aligned by a second „piggy-back“ continuous NiTi arch from the molar auxilliary tube to the contralateral molar auxiliary tube.
- 77. The NiTi archwire should be tied initially only to the canine and to the ground arch at the midline. Its force can be increased by tying further distally on the anterior segment. Although anchorage should be good with a stiff bypass arch , the extrusion force on the canine should be kept low using a NiTi arch with small diameter like 0.010 in or 0.012 in
- 78. The NiTi wire goes through a auxilliary slot in the bracket It works by trying to get back to its original stretched out state, thereby pulling on the impacted tooth. To get the pull effect though, the ends of the elastic wire have to be able to run freely.
- 79. A sectional piggyback NiTi wire is engaged in the maxillary left canine Double L LOOP to align highly placed maxillary canine (a) Auxiliary T-loop (0.0175 × 0.025
- 80. Canine bypass archwire. (a) Before canine root movement. (b) After treatment. Undesirable effects are eliminated on the adjacent teeth. The Biomechanical Foundation of Clinical Orthodontics Author(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu Canine bypass archwire
- 81. . A cantilever canine root spring during partial lingual treatment. (a) Before canine root movement. (b) After root movement. (c) Occlusal view. The canine is tied back using elastics on the lingual side to prevent mesial movement. The force system of the root spring produced a desirable moment, and the extrusive force helped to erupt the canine that was in infra-occlusion (red arrows in a). The Biomechanical Foundation of Clinical Orthodontics Author(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu Cantilever for canine extrusion
- 82. Cantilevers (0.017-inch x 0.025-inch CNA) were placed bilaterally from the auxiliary tube of the molar bracket to bring the highly placed canines into the arch .. Further alignment of the canines was done using a 0.016-inch nickeltitanium (Ni-Ti) wire piggybacked over a stiffer 0.017-inch x 0.025-inch CNA base archwire Cantilever for canine extrusion The Biomechanical Foundation of Clinical OrthodonticsAuthor(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu
- 83. Cantilever for canine extrusion. by means of SAT, the desired movement is achieved when force is directly applied to the mal-positioned/impacted tooth, while reactive force is dissipated or controlled in the posterior anchorage unit as a result of an increase in the number of teeth joined to the segment and/or the use of an anchorage appliance. Segmented arch or continuous arch technique? A rational approach Dental Press J Orthod. 2014 Mar-Apr;19(2):126-41
- 84. A) System of forces produced by a cantilever (statically determined system).This system also reveals a tendency towards palatalization of #13 with force going in the vestibular direction of CRes. B) Palatal bar used to control any undesired effects on the anchorage unit. - System of forces produced by a rectangular loop (statically undetermined system). The activated rectangular loop (light blue) must be adjusted so as to determine the final position of the tooth. When inserted into the slot (dark blue), its deactivation will move the tooth in the previously established position. A cantilever can be described as a segment of a stainless steel 0.017 x 0.025-in wire or a β-Ti wire inserted inside a bracket or tube in the reactive member, tied to the opposite end by means of contact point in the active member (impacted or malpositioned canine). Cantilever for canine extrusion
- 85. Therefore, the wire is not inserted into the bracket slot where movement is desired. Should the force produced by an activated cantilever (ranging from 40 to 60 gf) be directed along the CRes of the tooth, it will produce a translatory movement. Should it bypass the CRes of the tooth (in most cases, it is applied to the crown), it will result in a rotational tendency of force due to the moment of force established Cantilever for canine extrusion
- 86. Conversely, given that the wire has been inserted inside the bracket slot or tube, a force of equal intensity and opposite direction is observed in the reactive member. Similarly, a torque is produced inside the appliance when the moment arm of the activated cantilever is tied to the tooth to be moved. Such torque produces movement that, in association with force, must be restricted or reduced to nothing by reinforcing the anchorage of the reactive member (for instance, by using a palatal bar), so as to avoid side effects on the mechanics. Cantilever for canine extrusion
- 87. Class II malocclusion with accentuated occlusal plane inclination corrected with miniplate: a case report Marcel Marchiori Farret, Milton M. Benitez Farret Dental Press J Orthod. 2016 May-June;21(3):94-103 The introduction of skeletal anchorage has increased the number of treatment options for those cases with occlusal plane inclination. Mini-implants or miniplates may aid intrusion of a group of teeth, either in the maxillary or mandibular arches, without adverse effects while greatly reducing total treatment time.
- 88. CASE REPORT Diagnosis and etiology A 29-year-old woman sought orthodontic treatment, complaining about an unesthetic smile due to occlusal plane inclination and midline deviation. This was caused by absence of maxillary left lateral incisor and mandibular left second premolar, with ankylosis of deciduous molar in this region. Facial analysis revealed good symmetry and vertical balance of the facial thirds, a convex profile, and accentuated occlusion plane inclination in a smiling photograph.
- 89. Intraoral analysis revealed Angle Class II, Division 1 malocclusion, with absence of maxillary left lateral incisor, a peg-shaped maxillary right lateral incisor and the presence of mandibular left deciduous ankylosed second molar, which caused asymmetry on this side in both maxillary and mandibular arches (Figs 2 and 3).
- 90. Maxillary midline was deviated 2 mm to the left while mandibular midline was deviated 2 mm to the right. Panoramic and periapical radiographs confirmed the absence of maxillary lateral incisor and mandibular second premolar and also revealed mandibular teeth greatly inclined towards the ankylosed deciduous molar. Initial lateral cephalogram and cephalometric tracing revealed skeletal Class II malocclusion, with upright maxillary incisors and well-positioned mandibular incisors .
- 92. Treatment objectives The objectives of treatment were as follows: 1. Correct occlusal plane inclination. 2. Obtain molar Class I relationship on the left side and Class II on the right side. 3. Establish canine Class I relationship on both sides. 4. Correct midlines. 5. Extract deciduous molar and replace the tooth with implant-prosthetic rehabilitation. 6. Open space in order to implant a prosthetic rehabilitation of the maxillary left lateral incisor.
- 93. Orthognathic surgery was considered for occlusal plane correction, but the patient refused this option. Therefore, two other alternatives were considered to correct Class II malocclusion and tooth absences. The first option was to extract the maxillary right lateral incisor, replace lateral incisors with canines, and then replace canines with first premolars. This option was rejected in a meeting with the dentist responsible for the final rehabilitation.
- 94. The dentist believed that the esthetic result would be better with implant-prosthetic rehabilitation of the maxillary lateral incisor, as maxillary canines had large crowns and were too different in color, so as to be used as lateral incisors. The second option was to extract maxillary right first premolar and insert a mini-implant or miniplate on the left side to move the maxillary right dentition posteriorly.
- 95. This option was rejected by the patient due to longer treatment time required in comparison to that for first premolar extraction to distalize all teeth. Thus, in agreement with the patient and the other dentist, it was decided to correct the occlusal plane by means of a miniplate on the maxillary left side, extract the maxillary right first premolar and open space for rehabilitation of the maxillary left lateral incisor.
- 96. Treatment progress Treatment began with the bonding of 0.022 × 0.028-in standard Edgewise brackets on both arches, followed by alignment and leveling with 0.012 and 0.014-in Nickel- Titanium archwires and from 0.014-in to 0.020-in stainless steel archwires. Thereafter, maxillary right first premolar and mandibular left second deciduous molar were extracted and maxillary anterior teeth were moved to the right, tooth by tooth, with elastomeric chains, in order to correct maxillary midline and open space, thus allowing the insertion of an implant in the space left by the maxillary left lateral incisor.
- 97. On the maxillary left side, after correction of premolars rotation, a 2-mm space was created and both premolar and canine were distalized with elastomeric chains to increase the space for implantation of the maxillary left lateral incisor prosthesis and to partially correct Class II. On the mandibular arch, an implant was inserted into the space of the missing premolar to aid mandibular midline correction.
- 98. That implant was positioned above the proper position, considering that after occlusal plane correction with maxillary intrusion and mandibular extrusion on this side, the implant would be in adequate vertical position. Likewise, the implant was positioned closer to the mandibular left first molar and away from the left first premolar, thereby allowing distalization of mandibular left molars and distalization of mandibular anterior teeth, thus correcting the midline.
- 99. After that, a miniplate in the shape of an Y was inserted in left zygomatic buttress and used to intrude all maxillary left teeth, with elastics connected to 0.019 × 0.025-in wire segments inserted into a tube and connected to a miniplate, generating a force of 200 g/f each .
- 100. Furthermore, the miniplate was used to distalize all teeth on the left side, with elastomeric chains connected to a hook welded between the lateral incisor and canine, so as to correct Class II relationship. After correction on the maxillary arch, the mandibular arch was extruded with intermaxillary 1/8-in elastics connected directly to the miniplate and on the mandibular teeth and archwire (Fig 6). (C and D) elastic mechanics employed to extruded mandibular left teeth,
- 101. E to G) after mandibular extrusion, (H to J) after miniplate removal and during the finishing procedures.
- 102. In order to allow mandibular teeth extrusion, the mandibular arch was made bypassing the bracket of provisory crown over the implant. At that time, the space for maxillary left lateral incisor was already well defined and the implant was inserted. Maxillary right lateral incisor was provisionally restored with composite resin before appliance debonding, so as to precisely define the spaces on the anterior region. After 34 months of treatment, the appliance was removed. (C and D) elastic mechanics employed to extruded mandibular left teeth,
- 103. Treatment results At the end of treatment, we noticed an improvement in smile esthetics due to correction of occlusal plane inclination and because the midlines were coincident with the facial midline . The profile remarkably improved as a result of counterclockwise rotation of the mandible, which reduced convexity, thus increasing the prominence of lips and chin .
- 104. Intraoral and dental casts analyses revealed that Class I molar relationship on the left side, Class II molar relationship on the right side and Class I canine relationship on both sides were all obtained, with good intercuspation.
- 105. Panoramic radiograph showed good parallelism among roots, in addition to root resorption on maxillary left central incisor, which will be monitored after treatment. Post-treatment lateral cephalogram, cephalometric tracing and superimposition examinations confirmed accentuated mandibular counterclockwise rotation
- 106. Furthermore, maxillary left molars were intruded while mandibular molars were uprighted and extruded. Maxillary and mandibular incisors were proclined after treatment. The patient will be monitored every six months in order to have root resorption and treatment stability controlled.