Orthodontic Functional Appliances E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 338

Veröffentlichungsjahr: 2016

Beschreibung

Comprehensive specialist manual covering the science and practice of functional appliance therapy

• Integrates clinical and academic elements with emphasis on evidence-based research and its clinical application
• Suitable for trainee and practicing orthodontists
• Includes more than 600 photographs to enhance clarity of topics covered
• Features contributions from top clinicians and researchers in the field

Leseprobe

Table of Contents

Cover

Title Page

List of contributors

Preface

CHAPTER 1: Biological basis for functional appliance therapy

Facial growth

Function and craniofacial morphology

Experiments on primates

Other animal studies

The visco-elastic theory

Treatment duration

Maxillary restraint

Summary

References

CHAPTER 2: Development of functional appliances

Activators

Bionator

Functional regulator

Twin Block

Fixed functional appliances

Herbst

Fixed mandibular advancement appliances

Summary

References

CHAPTER 3: The role of genetics and environmental factors on the condyle in mandibular growth

Genetic control of condylar growth

Evidence from animal experiments: Condylar injury, transplantation and growth factors

Response of the condyle to postural or mechanical changes

Functional/biochemical interface

Environmental influences through functional appliance therapy

Overall control of mandibular growth

Summary

References

CHAPTER 4: Functional appliance therapy

Age

Growth pattern

Vertical skeletal pattern

Antero-posterior skeletal pattern

Transverse skeletal abnormality

Occlusal features

Soft tissues

Compliance

Indications for specific appliances

Summary

References

CHAPTER 5: Clinical use of the Twin Block appliance

Case selection

Impressions

Bite registration

Appliance design

Fitting the appliance

Follow-up appointments

Breakages

Overjet and reversed overjet

Length of retention

Space planning for fixed therapy

Post-treatment retention

Summary

References

CHAPTER 6: Rigid fixed functional appliances

Herbst

Mechanism of Class II correction

Lower incisor changes

Vertical effects

Timing of Herbst treatment

Soft tissue effects

Mandibular Anterior Repositioning Appliance (MARA)

Comparison of fixed functional appliances

Summary

References

CHAPTER 7: Flexible fixed functional appliances

Jasper Jumper

Forsus

Twin Force

Eureka Spring

Summary

References

CHAPTER 8: Transferring from functional to fixed appliances

Planning the transition

Cephalometric superimposition

Timing

Methods of consolidating Class II correction

Conclusions

References

CHAPTER 9: The use of functional appliances in the correction of Class III malocclusion

Aetiology of Class III malocclusion

Early treatment

Mechanisms of Class III correction

Case selection

Functional appliances for Class III correction

Summary

References

CHAPTER 10: Functional appliances

Levels of evidence and evidence-based dentistry

Primary study design (randomized and non-randomized studies)

What are the short-term effects of functional appliances on the skeletal pattern?

What are the short-term effects of functional appliances on the dentition?

What are the effects of functional appliances on the soft tissues?

What are the long-term effects of functional appliances on the dentition, supporting structures and soft tissues?

What is the optimal timing for functional appliance therapy?

Are fixed or removable functional appliances more effective?

Research in context

Summary

Appendix

References

CHAPTER 11: Cases

QH

FA

AS

GC

ML

HF

Index

End User License Agreement

List of Tables

Chapter 07

Table 7.1 A comparison of the effects of various fixed functional appliances in conjunction with comprehensive fixed Edgewise appliances. Studies were excluded if there was a delay in treatment between the fixed functional appliance and comprehensive Edgewise appliances treatment, as this extended the overall observation period. Molar correction and overjet were either measured directly or, if that was not available, the change in relation to a vertical reference line was used.

Chapter 08

Table 8.1 Relative merits of options to manage the transition from functional to fixed appliances.

Chapter 10

Table 10.1 Uses, advantages and disadvantages of case-control and cohort studies.

Table 10.2 Types of bias encountered in randomized controlled trials.

Table 10.3 Maxillary incisor retroclination with functional appliances.

List of Illustrations

Chapter 01

Figure 1.1 Resorption on the superior surface of the maxilla accompanied by deposition on the palate surface leads to an inferior displacement.

Figure 1.2 Mandibular growth occurs via condylar growth in a posterior and superior direction resulting in downward and forward displacement. Resorption on the anterior surface of the ascending ramus combined with resorption on the posterior surface leads to forward movement of the ramus.

Figure 1.3 An example of the effects of cranial binding in a South American female from the Atacama desert. Typically, binding is undertaken for a relatively short period (approximately 6 months) in infancy; the effects are marked and persist into adulthood.

Figure 1.4 Skeletal II discrepancy is typically related to mandibular retrognathia rather than maxillary protrusion. However, analysis of the Burlington, Bolton and Ann Arbor samples demonstrated that 49% of skeletal II patterns were associated with SNA values below 81 degrees. Moreover, SNB was below 78 degrees in 82% of the sample.

19

Therefore, much of the focus of growth modification has been on the propensity to effect lasting change on mandibular position and dimensions. McNamara subsequently developed a cephalometric analysis involving a facial vertical line drawn perpendicular to the Frankfurt plane.

20

Figure 1.5 Schematic representation of the mature rat mandible. The rabbit and mouse mandibles have a similar morphology with a short ramus and relatively pronounced angle.

Figure 1.6 Harvold activator (a–e). The inter-maxillary force should theoretically be concentrated on both the maxillary dentition and palate, while the forces are transmitted to the lingual aspect of the mandible rather than the lower teeth. Consequently, well-extended lower impressions with adequate lingual depth, in particular, are required. The postured bite is taken 8–10 mm beyond the freeway space with near maximal protrusion, this degree of vertical opening allows the inclusion of an anterior breathing hole. During fabrication, extensive plaster relief is important in the lower posterior region to promote full eruption and lower arch levelling, while restricting unwanted lower incisor proclination with extension of the lower anterior acrylic onto the labial aspect of the mandibular incisors (c). The molars are afforded space to erupt, particularly in the lower arch to facilitate arch levelling and overbite reduction. An upper labial bow in 0.8 mm spring hard stainless steel may be added to facilitate retention, although more flexible wire may be used where space closure in the upper anterior region is planned. The labial bow should permit eruption and distal movement of the maxillary canines where required. The relief for the upper posteriors is such that it provides cusp tip contact with the upper acrylic plate with no interference, which might inhibit distal movement of the upper posteriors (d, e). These elements are usually introduced during the fabrication stage, with chairside trimming not usually required. The upper anterior aspect of the acrylic plate should extend to the incisal edges of the maxillary incisors to facilitate three-dimensional control, and a relief chamber is provided palatal to the incisors to facilitate intrusion without retraction.

Chapter 02

Figure 2.1 Andresen activator (a–d). Andresen believed that his passive appliance affected both the activity of the musculature and associated circulation, leading to an increase in biomechanical forces. The appliance involved little wirework, with early designs incorporating a coffin spring, although this is not now typical of the appliance. There is an upper labial arch, which can also involve loops to control the position of the maxillary canines. The labial bow is effectively passive and constructed from 0.9 mm spring hard stainless steel wire. The wire tagging enters the posterior blocks distal to the canines, elevated above the occlusal level of the contact points of the canines and premolars of the maxillary dentition. The tag ends of the labial bow should rest free of the maxillary dentition. The lower anterior teeth are held within the acrylic. Mandibular incisor proclination was common with this appliance, leading to lower anterior spacing. Fränkel, among other later developers, was critical of this and strove to limit forces to the lower anteriors to reduce proclination. Extensive functional trimming was typical of the Andresen in both the upper and lower regions of the posterior capping, but also the upper anterior palatal aspects of the appliance. This was designed to induce a ‘bite thrust’, as the patient continually bites into the appliance. Correct trimming of the posterior blocks should facilitate distal and transverse development of maxillary posteriors; directionally trimmed facets created at the chair-side permit the upper half of the posterior blocks to engage preferentially on the mesial aspects of the maxillary premolars and molars to encourage the desired tooth movement. The anterior palatal region of the appliance is trimmed on the fitting surfaces behind and along the anterior teeth. The space created allows posterior movement of the maxillary anteriors due to the unrestrained activity of the upper labial bow and soft tissues. Facets are present in the lower half of the posterior blocks only in the vertical plane, ensuring that they do not interfere with the vertical development of the mandibular posteriors. Judicious vertical trimming of the mandibular half of the blocks also prevents unwanted lingual tipping of the mandibular posterior teeth over the course of the functional phase.

Figure 2.2 Bionator (a–e). Balters believed in the centrality of normal soft tissue pattern and behaviour in the development of facial form and inter-maxillary relationships. As such, he emphasized the pivotal nature of the education of soft tissues, including improvement of lip seal and tongue posture and function, even publishing a paper on the ‘self-healing’ of malocclusion due to elimination of aberrant soft tissue patterns and behaviour. By advancing the mandible with the postured bite, Balters opined that dynamic space within the mouth was increased for functions including breathing and speech. The space for the tongue would also be increased with improved vascularization and lymphatic exchange. The appliance incorporates a vestibular and palatal arch and a resin body. The construction bite is normally taken with the incisors in an edge-to-edge relationship. The labial arch was initially suggested in an attempt to train the upper lip, promoting lip competence by introducing a stimulus for lip closure. Balters recommended prolonged wear of up to 20–22 hours daily, believing that the reduced bulk resulted in limited impairment of oral functions including speech, although removal was recommended for eating, oral hygiene, wind instruments and sport. The vestibular wire is fabricated from 0.9 mm spring hard stainless steel wire, with the palatal connector 1.2 mm in dimension. The vestibular wires should extend no further posteriorly than the mid-buccal groove of the maxillary first molars with separation of approximately 1 cm between upper and lower vestibular wires in the posterior region; it should also be clear of the teeth without encroaching on the buccal mucosa. There should be adequate clearance between the wire contouring labially and that in the vestibular region.

Figure 2.3 FR2 (a–g). Fränkel’s appliances were based on his belief that the soft tissues were central to the development of malocclusion. He also aimed to restore normal muscle function with treatment. Consequently, the FR2 had vestibular shields to remove the influence of the buccal musculature on the dentition, allowing unopposed expansion due to the position and activity of the tongue. Moreover, by incorporating buccal shields Fränkel believed that more room was given to the tongue to allow tongue exercises to be undertaken. He also felt that this altered tongue behaviour would induce new bone in palatal growth sites, with minimal tipping of posterior teeth due to periosteal stretching. Moreover, the buccal shields and lower anterior palots were intended to induce traction on the periosteal layer, stimulating bone formation. The buccal shields are relieved 2.5 mm in the upper half and 0.5 mm in the lower half to facilitate expansion. Fränkel aimed to limit direct forces to the teeth from the wirework, with lower lingual shields designed to influence periodontal receptors and the mucosa, reflexly activating mandibular protractor muscles rather than allowing proclination of the mandibular incisors. He believed that forward mandibular posture was maintained by neuromuscular activity due to contraction of the extensor muscles rather than actively by the components of the appliance, suggesting that this would translate into less mandibular incisor proclination. The absence of occlusal rests on the lower dentition means that the vertical dimension is maintained by the height of the buccal shields. Consequently, while trimming of the shields may be undertaken in an effort to improve comfort and compliance, this may influence the vertical dimension and risk placing excessive forces from the lingual resting wires on the lower incisors causing further proclination, as these may contact the lower incisors in a more gingival position. Where excessive mandibular incisor proclination occurs, consideration may be given to removal of the lingual wires to allow the mandibular incisors to upright into a more stable position. The lingual pad is the heart of the appliance; it is carried by the lingual hangar and the lingual springs. The hangar is fabricated from 1.5 mm spring hard stainless steel with the lingual springs 0.7 mm in dimension; 0.9 mm spring hard stainless steel wires emerge from the buccal shields inferior to the teeth to carry the lower labial palots. Anteriorly the labial palots are relieved by 0.5 mm and they should not extend to the occlusal level of the lower incisors. The anterior labial bow is fabricated in 1 mm wire emerging from the buccal shields, rests gently against the maxillary incisors and is free of the canines. Recurved canine clasps are sited in the canine region and are not designed to engage with the canines. The anterior transpalatal wire is made in 0.9 mm spring hard stainless steel placed posterior to the cingulum of the maxillary incisors and features U-loops at its extremity that terminate in the buccal shields. The posterior transpalatal wire is made in 1.2 mm wire; it is recurved in the terminal aspect overlying the occlusal surfaces of the first molars.

Figure 2.4 A 12-year-old female presented with a Class II division 1 incisor relationship in the early permanent dentition, with an increased overjet of 11 mm and Class II molar relationships bilaterally (a–f). There was a lower lip trap with a deep labio-mental groove, with the lower incisors upright on the lower dental base. An FR2 was fitted with lower labial palots and an upper labial bow (g). The lower palots were placed inferior to the lower incisors in the labial sulcus with the appliance fully engaged, inducing periosteal stretch. The appliance was worn for a period of 12 months resulting in full correction of the malocclusion with unfurling of the lower lip and a resultant advancement of the lower incisors; much of the overjet reduction was attributable to mandibular incisor proclination (h–p). The occlusion was detailed with fixed appliances thereafter over a period of 9 months (q–y).

Chapter 03

Figure 3.1 Arrangement of bone-producing cells within condylar growth sites. Specific differences relative to endochondral ossification in long bones include the haphazard arrangement of the cartilage-producing cells and the presence of a layer of dense fibrous connective tissue.

Figure 3.2 Experimental evidence for control of condylar growth.

Chapter 04

Figure 4.1 Cervical vertebral maturation (CVM) technique.

Figure 4.2 This 12-year-old female presented with a Class II division 1 incisor relationship on a skeletal II pattern. The malocclusion was complicated by a combination of increased overjet of 8 mm, upper and lower anterior malalignment and a unilateral posterior crossbite with displacement to the right side (a–i). She was treated with a modified Twin Block appliance for a period of 9 months to address the Class II element. The transverse issue was partially addressed during the functional phase with upper arch expansion (j–l). However, a crossbite tendency remained. This was resolved during the subsequent fixed phase (m–o). Total time for active treatment was 20 months. An upper Hawley retainer in conjunction with upper and lower bonded retainers was placed to retain the result (p–x).

Figure 4.3 This 12-year-old male presented with a significant skeletal II discrepancy and mandibular asymmetry related to traumatic injury to the left condyle in infancy (a). This had resulted in a significant maxillary cant; mouth opening was also restricted (See Chapter 11). He was treated with mandibular distraction to address the skeletal II discrepancy and asymmetry in adolescence, resulting in increase in the ramal height on the left side and leading to a significant open bite on that side (b). A hybrid functional appliance with occlusal coverage on the right side only was fitted to maintain Class II correction while promoting vertical development of the left maxillary dentition (c, d). Fixed appliances were subsequently placed to settle the buccal occlusion.

Figure 4.4 This 11-year-old female presented with an increased overjet of 12 mm. The molar relationships were Class II bilaterally. The maxillary incisors were spaced and proclined at 125 degrees to the maxillary plane with a lower lip trap. In this instance a modified Twin Block was fitted to address the Class II dental and skeletal relationships. An upper labial bow was incorporated to promote uprighting of the maxillary incisors. The labial bow was activated with the acrylic palatal to the incisors trimmed (j, k). The overjet was addressed with a combination of skeletal and dento-alveolar changes.

Figure 4.5 This 12-year-old female was referred by her orthodontic specialist in relation to her increased overjet. Extra-orally she had a moderate skeletal II pattern with increased lower anterior facial height and FMPA. The lips were incompetent, with 6 mm of incisal display at rest and 3 mm of gingival exposure on smiling. There was crowding in both arches and an overjet of 12 mm (a–h). The aims of treatment included improvement in the skeletal II discrepancy and correction of the incisor relationship. However, significant further increase in the vertical dimension would be undesirable facially, risking further lip incompetence, and from an occlusal standpoint, as reduction in the overbite was not required. While a Twin Block may have been considered in this case, it may have risked further increase in the vertical dimension, necessitating vertical control possibly with headgear. Notwithstanding headgear use, further vertical increase would have been difficult to avoid. Consequently, a Dynamax appliance was used in this case in conjunction with orthopaedic headgear (i, j). Limitation of increases in lower anterior face height may be facilitated by restraint of vertical maxillary growth; supplementary use of orthopaedic headgear and use of specific functional appliances, e.g. Teuscher, van Beek, Dynamax, have been proposed to achieve this. The Dynamax was used in isolation for 9 months in this case before committing to extraction of four second premolar units to facilitate relief of crowding and arch alignment. The functional appliance was maintained while initial alignment was achieved with fixed appliances, eliminating the need for the interim stabilization phase required with many removable functional appliances (k–n). Fixed appliances were subsequently used for 18 months to align the arches (o–q), closing the extraction spaces and resulting in solid buccal segment interdigitation favouring stable Class II correction. The final result is shown in r–y.

Figure 4.6 The Dynamax appliance (a–f) incorporates a modified lower lingual arch with lingual shoulders or steps designed to accommodate vertical projections from the upper component to maintain forward mandibular posture following an initial 3–4 mm of advancement by encouraging an avoidance reflex. The vertical projections are activated incrementally by approximately 2 mm on a bimonthly basis to effect a gradual Class II correction. The upper component involves torquing spurs in 0.7 mm spring hard stainless steel to the upper central incisors, limiting unwanted retroclination of the incisors, and therefore promoting maximal forward development of the mandible. A midline spring may be incorporated in the upper appliance to facilitate transverse increase; this was activated in the present case from the outset. The upper removable component also involves posterior capping with a 1 mm layer of acrylic, acting to disengage the occlusion and facilitating sagittal correction. By limiting vertical opening, vertical maxillary growth may theoretically be restrained allowing more horizontal expression of mandibular growth, reducing any downward–backward rotational effects of appliance therapy. Adjunctive use of orthopaedic headgear may have an additive effect in terms of restraining maxillary vertical growth, although there is little evidence to support this approach.

Figure 4.7 This 11-year-old female presented with a Class II division 1 incisor relationship on a moderate skeletal II pattern. She had an increased overjet of 11 mm with reduced vertical dimensions and an associated increased overbite. There was also generalized spacing and bimaxillary proclination, with the lower incisors at 113 degrees to the mandibular plane (a–i). A modified Twin Block was chosen to promote Class II correction with a concomitant increase in the vertical dimension. A lower sectional fixed appliance was placed in conjunction with the functional appliance to upright the lower incisors, promoting maximal skeletal correction of the Class II malocclusion by removing pre-existing dento-alveolar compensation (j). Comprehensive fixed appliance–based treatment was then undertaken over a period of 12 months to detail the final occlusion (k–s).

Figure 4.8 The median opening activator (a–d) has lower incisor capping, allowing posterior disclusion to facilitate overbite reduction (e, f). Posterior settling of the occlusal occurred over a 12-month period following withdrawal of the appliance (g, h). Cribs and occlusal rests are fabricated from 0.8 mm spring hard steel and a cingulum wire from 1 mm steel from canine to canine (i–n). The labial bow was described in 0.9 mm spring hard stainless steel. There are acrylic columns (l) in the canine–premolar region linked to a saddle upper plate, which is free of the upper anterior region.

Chapter 05

Figure 5.1 A Class II division 2 malocclusion with retroclined maxillary central incisors and Class II buccal segment relationships (a, b). A modified Twin Block was placed in conjunction with a sectional fixed appliance to advance the maxillary incisors during the fixed appliance phase (c, d). Consequently, Class II correction could be undertaken in concert with upper anterior alignment (e–g). A similar case is shown in h–l. A sectional fixed appliance was placed with progression into rectangular stainless steel wires to allow torque expression (m–o). Decompensation of the maxillary incisors was accomplished in conjunction with molar correction, with overcorrection of the molar and canine relationships and creation of lateral open bites after 8 months of therapy (p–s). Rotation of the maxillary canines may be reduced with incorporation of the maxillary premolars in the sectional fixed appliance during the functional phase, but alternatively can be easily addressed during the comprehensive fixed phase. The final occlusal result is shown in (t–x).

Figure 5.2 Wax bite registration on a patient with an increased overjet and overbite with an increased curve of Spee (a–c). Opening of 2–3 mm has been achieved anteriorly, with the wax approximately 6–7 mm thick in the premolar region to allow adequate block height without excessive anterior opening (d–h).  The use of a blue acrylic Exacto Bite Stick

TM

is also shown (i–k). The acrylic is 2 mm thick anteriorly and has grooved upper and lower surfaces. The maxillary incisors are allowed to seat into one of three upper grooves to control the amount of mandibular advancement. The mandibular incisors fit into the single groove on the lower surface. The anterior thickness of 2 mm should control the vertical opening anteriorly, resulting in a well-tolerated and comfortable appliance. In this instance full seating was not achieved anteriorly, resulting in a corresponding increase in the height in the premolar region (k). A further record is shown (l) with full seating anteriorly, corresponding to a minimal (2 mm) opening. The wax thickness is greatest in the premolar region before reducing in the molar region, reflecting the orientation and depth of the occlusal curve.

Figure 5.3 A 10-year-old female presented in the mixed dentition with an increased overjet of 10 mm to a proclined maxillary right central incisor with upper anterior crowding (a–h). A sectional fixed appliance was placed to align and locally decompensate the maxillary incisors, with concomitant use of a Twin Block to correct the Class II relationships as an interceptive treatment phase. Maxillary first permanent molars and first primary molars were used as retention. Adams’ cribs were placed on the lower first molars with a lower anterior labial bow (i–l). After 9 months of appliance therapy, the initial phase was completed with placement of an upper bonded retainer prior to establishment of the permanent dentition and definitive treatment in the permanent dentition (m–t).

Figure 5.4 In this 13-year-old female with delayed dental development in the late mixed dentition, a ball-ended clasp was placed in the upper primary molar region as the first premolar had not erupted. As the lower right first premolar was close to erupting, an Adam's clasp was incorporated in the design and used at a later stage once the tooth had erupted sufficiently to offer retention (a-h).

Figure 5.5 A 12-year-old male presented with a Class II division 1 incisor relationship in the early permanent dentition, with a large overjet of 12 mm and Class II molar relationships bilaterally (a–c). A modified Twin Block was fitted with one-step advancement to fully eliminate the overjet (d–i), resulting in overcorrection of the malocclusion to Class III molar relationships bilaterally. Significant lateral open bites arose due to the presence of the acrylic blocks allied to clasping of the first permanent molars. The upper appliance was trimmed to allow for regression of the lateral open bites prior to proceeding with fixed appliance therapy. This occurred over a 6-week period of part-time wear (j–o). Further resolution occurred without recourse to inter-arch elastics during the fixed appliance phase (p–u). The final occlusal result is shown in (v–x).

Figure 5.6 This female adolescent had a period of Twin Block wear to correct a significant Class II malocclusion with increased overjet of 12 mm. Trimming of the blocks was not undertaken during the functional phase, with pronounced resultant lateral open bites ensuing (a–f). Fixed appliances were placed without a pause to permit spontaneous resolution due to the likely need for a protracted fixed phase because of the degree of crowding and centre-line discrepancy (g–i). Spontaneous resolution of the lateral open bites occurred over a period of 10–12 weeks (j–l). Fixed appliance treatment was completed to enhance the posterior interdigitation, improving the prospect of prolonged stability (m–o).

Figure 5.7 A further Class II division 1 case with an overjet of 9 mm (a). The malocclusion was fully corrected with a modified Twin Block (b). The blocks were relatively shallow, with limited lateral open bites accruing despite lack of acrylic trimming (c, d). Lateral open bites were closed during the fixed phase (d, e) due to their relatively limited extent and the presence of reasonable intercuspation; hence, condylar stability occurred relatively early in the fixed phase. A similar situation with shallow (5 mm) blocks is given in f–i. The blocks also met at approximately 45 degrees rather than the recommended, more positive 70-degree intersection that Clark now recommends. Notwithstanding this, forward posture was maintained and the resultant lateral open bites were minimal despite diligent wear of the appliance.

Figure 5.8 A significant Class II malocclusion with an overjet of 10 mm (a) was corrected fully with a Twin Block over a period of 9 months, resulting in lateral open bites and over-correction of the molar relationships (b). On maximum protrusion there was a reverse overjet of 3 mm (c), confirming that the Class II correction was genuine and not attributable to habitual posture.  A similar case with a slightly larger overjet (d–f) was treated with a Twin Block (g–i), resulting in full Class II correction (j–l). Maximal protrusion highlights the degree of genuine change, with a frank reverse overjet of 6 mm in the most protruded position. Maximal protrusion highlights the degree of genuine change, with a frank reverse overjet of 6 mm in the most protruded position (m, n).

Chapter 06

Figure 6.1 This Herbst appliance incorporates crowns as anchorage on the molars (a, b) and is cantilevered in the lower arch. The upper component may include a trans-palatal arch to maintain arch form and reduce buccal flaring of the molars. In cases requiring transverse expansion to coordinate the arch width, an expansion device may be used (a). The expansion can be completed prior to adding the side arms (c–f), which consist of an upper tube and a lower rod. If the arms are added before the expansion, the angle of entry of the rod into the tube may cause binding and discomfort. The rods can be activated to advance the mandible further during treatment by the addition of pre-cut metal spacers (f), which slide onto the rod and can be crimped with a heavy set of pliers. The lower component includes a lingual arch (b) resting on the lower incisors to reduce mesial molar tipping.

Figure 6.2 This 11-year-old male was treated with a Herbst appliance in conjunction with an upper expander (a–h). After 1 month of expansion and 8 months with the Herbst, a significant improvement in the overjet was achieved and the appliances removed. An upper Hawley retainer was made to retract the upper incisors slightly (i–p). The patient was then monitored until he was 14-years-old and on eruption of the remaining permanent dentition, the patient and his family chose to accept the final alignment and occlusion (q–x).

Figure 6.3 The patient presented at age 11 years with a persistent thumb habit and associated open bite and constricted maxillary arch in addition to a Class II malocclusion. To reduce reliance on compliance, a Herbst appliance was chosen in conjunction with a maxillary rapid palatal expander, which was activated over 5 weeks. After 2 months the side arms were added to the Herbst to advance the mandible into an edge-to-edge occlusion. The Herbst was activated by an additional 2 mm once during treatment spanning 8 months to achieve the desired molar correction and then removed (a–h). The habit had reduced by 2 months and stopped completely by 7 months into treatment. After the Herbst treatment the family and child chose to accept the alignment and occlusion. The patient was monitored for 6 months while the occlusion settled and retainers made (i–p). Five years later the patient returned. Class II correction had been stable; however, retainers had not been worn and some crowding had occurred (q–x). The patient elected to finalize the alignment with Invisalign sequential aligners over a period of 19 months. This was followed by provision of fixed and removable retainers (y–af).

Figure 6.4 This 11-year-old female with a 10 mm overjet received a Herbst with an expander for a total of 8 months (a–h). The patient was treated to a super-Class I molar relationship and Class I canine with some residual space distal to the canine to allow for some relapse of the molar relationship. At this time the Herbst was removed and full pre-adjusted Edgewise appliances placed for 13 months. Class II elastics (5/16 inch, 3.5 oz) were used for 5 months during treatment to maintain the correction (i–p). Once treatment was complete, a lower bonded retainer and removable vacuum formed retainers were provided (q–x). Six years later the alignment and occlusion have held reasonably well, with some relapse of the left buccal occlusion and movement in the left premolar/canine region (y–af).

Figure 6.5 Herbst and Invisalign case. An adult female presented with a Class II division 2 malocclusion on a skeletal II pattern (a–h). A cast Herbst appliance was fitted with maxillary expansion (i, j). The appliance was in place for 9 months leading to over-correction of the Class II malocclusion with upper arch spacing (k–r). Thereafter, a clear aligner system (Invisalign

TM

) was used to address some Class II occlusal relapse (s, t) and to detail the occlusion (u–ab).

Chapter 07

Figure 7.1 The Forsus FRD is attached to the maxillary molar tube and in the lower arch either to a bypass wire or directly to the lower archwire, as pictured. When the patient closes the spring is compressed, but the mandible is not forced forward as with the rigid FFAs, although the patient may posture forward in some cases.

Figure 7.2 This 14-year-old female (a–h) had a ¼ unit Class II relationship on the right and ¾ unit Class II on the left side. She was treated with the Forsus FRD in conjunction with 0.018 inch pre-adjusted Edgewise appliances. The Forsus abutted against the lower canines, so rotational bends were placed to counteract the rotational moment from the rod pressing against them and tied with a stainless steel ligature to reduce the risk of breakage by the Forsus pressing against the tie. No trans-palatal arch was used, as the second molars were included with a 0.017 inch x 0.025 inch stainless steel archwire to limit maxillary posterior buccal rolling and reduce posterior bite opening. Treatment was completed in 19 months with 5 months of Forsus wear, which was more active on the left side due to the requirement for greater correction on that side (i–p).

Figure 7.3 An ulcer on the cheek has resulted from the fixed functional appliance. Care kits including ulcer gels and cotton rolls to hold the cheek away from the device help to reduce the incidence of ulcers until the cheek mucosa toughens and the patient adapts to the device. However, once an ulcer has developed, the appliance may need to be removed temporarily to allow resolution.

Figure 7.4 For each appliance the molar correction in millimetres was combined from Table 7.1 and the blue line represents the range of reported mean values. The purple square represents the mean molar change of the combined data weighted by the number of subjects in each group.

Figure 7.5 The appliance efficiency (molar change in millimetres per year) was combined from Table 7.1, with the blue line representing the range of reported mean values. The purple square represents the mean appliance efficiency of the combined data weighted by the number of subjects in each group.

Chapter 08

Figure 8.1 Class II effect on maxillary and mandibular arches with distal tipping of upper buccal segments and mesial tipping of the lower arch associated with a Twin Block appliance.

Figure 8.2 This 8-year-old male presented with concerns in relation to his dentofacial appearance with reports of associated teasing (a–i). A decision was, therefore, made to carry out interceptive treatment to reduce the overjet at least partially during the first treatment phase. A further objective of the initial phase was to achieve lip competence. A modified Twin Block was worn for a period of 9 months on a full-time basis resulting in antero-posterior correction and lip competence (j–l). In view of the stage of dental development with multiple retained primary teeth, definitive correction was delayed (m–q). The functional appliance was therefore maintained on a nights-only basis for a further 12-month period before being withdrawn for a further 12 months. Thereafter, a second treatment phase was instituted involving fixed appliances on a non-extraction basis. In this instance, sagittal relapse of the Class II did not arise during the intervening period, ensuring that a second phase of functional appliance therapy or other form of Class II correction was not required during Phase 2 (r–z).

Figure 8.3 This 12-year-old male presented with a very significant overjet (15 mm) on a moderate skeletal II pattern with mandibular retrognathia and spaced arches. He reported teasing in relation to his dentofacial appearance (a–f). He was treated with a modified Twin Block for a period of 12 months. He was very compliant; the appliance was reactivated with light-cured acrylic after 8 months (g). The malocclusion was significantly overcorrected with the overjet fully eliminated and molar relationships overcorrected to Class III (h–j). Significant lateral open bites also reflect the excellent wear of the appliance. Subsequently, upper and lower fixed appliances were placed with restorative build-up of the maxillary lateral incisors to consolidate the spacing and seat the buccal occlusion. The overcorrection resolved during the fixed phase with a resultant Class I, well-interdigitated buccal occlusion (k–s).

Figure 8.4 This 11-year-old female presented with a Class II division 1 incisor relationship with an increased overjet of 10 mm. There was crowding of both dental arches (a–e). She was treated with a modified Twin Block to address the skeletal II pattern. Incisor and molar relationships were overcorrected during the functional phase (f–h). In view of the pre-existing crowding allied to proclination of the mandibular incisors during the functional phase, a space requirement existed to align the lower incisors in a stable position. Consequently, bands were fitted to the maxillary first molars to permit night-time headgear wear, while Class III elastics were used to upright the mandibular incisors. An acceptable final occlusal outcome was achieved (o–s).

Figure 8.5 Typical lateral open bites arising following Twin Block therapy (a, b) due to impeded vertical development of the posterior teeth related to the acrylic coverage, while continued eruption of the anteriors proceeds during the functional phase. These resolve rather easily during or prior to the fixed appliance phase (c).

Figure 8.6 This 12-year-old male presented with a large overjet (12 mm) on a moderate skeletal II pattern with mandibular retrognathia, crowding of both dental arches and proclined maxillary incisors with a lower lip trap (a–h). He was treated with a modified Twin Block over a 10-month period (i, j) before withdrawing the appliance for a period of 6 weeks. The molar relationships were overcorrected to ½ unit Class III with bilaterally and lateral open bites developed (k–n). Following withdrawal of the appliance, slight antero-posterior relapse occurred and the lateral open bites began to close (o–q). A decision was made to remove four second premolar units to facilitate relief of crowding and further retraction of the maxillary incisors (r–t).

Figure 8.7 This Class II malocclusion was treated with a Dynamax in the first instance to address the antero-posterior discrepancy (a–d). The Dynamax was maintained during the fixed phase to facilitate maintenance of the Class II correction as lower arch alignment proceeded (e–h).

Figure 8.8 Pronounced distal tipping of the maxillary posterior teeth has occurred, manifesting as space posterior to the maxillary canines allied to the distal angulation of the maxillary premolars and first molars (a–c).

Chapter 09

Figure 9.1 Fränkel functional regulator (a–g). The FR3 complemented Fränkel’s other designs, with the underlying principles including the centrality of the soft tissues to malocclusion and the importance of ensuring normal soft tissue behaviour. The upper labial pad is designed to act in a similar way to the lower labial palots, with periosteal stretching and modulation of the influence of the upper lip on the maxillary incisors. Moreover, the forces from the upper lip were designed to be transmitted through the appliance to the lower arch and dentition, as Fränkel aimed to limit the contact between the appliance and the upper arch. The anterior trans-palatal wire rests on the cingulum of the maxillary incisors with U-loops; it should lie below the maxillary occlusal plane as it crosses the upper arch, so as not to interfere with downward and forward development of the maxillary arch. It is made in 0.8 mm spring hard stainless steel. The posterior trans-palatal wire is made in 1.2 mm wire to afford sufficient rigidity. Its distal extension is posterior to the terminal molar to limit interference with forward maxillary development and finishes in the buccal shields. There are maxillary molar occlusal rests in 1 mm spring hard stainless steel, which also enter the plate distally. There is a labial arch in 0.9 mm spring hard stainless steel, which carries the two labial palots. It is important that the wire is kept straight in the tag portion for ease of re-activation of the appliance. The lower half incorporates a 1.2 mm spring hard stainless steel labial bow and occlusal rests on the lower first molars in 1 mm spring hard stainless steel. There is 3 mm relief for the upper half of the buccal shields, while no relief is built into the lower shields to lock the lower arch both transversely and in the antero-posterior dimension. The relief for the upper labial palots is also 3 mm.

Figure 9.2 Correction of Class III malocclusion with Fränkel functional regulator 3.

Figure 9.3 Superimposition of pre- and post-treatment lateral cephalograms for case shown in Figure 9.2.

Figure 9.4 Reverse Twin Block appliance. Note that the lower block occludes distally to the upper block. A lower labial bow aids in retention of the lower appliance and springs have been placed palatal to the upper incisors to procline them.

Figure 9.5 Correction of a Class III malocclusion with a reverse Twin Block appliance showing lateral open bites.

Chapter 10

Figure 10.1 Change in ANB with early functional appliance treatment and untreated control group.

Figure 10.2 Change in ANB with early headgear appliance treatment and untreated control group.

Chapter 11

Figure 11.1 Reproduced with permission from C. Siew-Yee.

Figure 11.2

Figure 11.3

Figure 11.4

Figure 11.5

Figure 11.6

Guide

Cover

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