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Marcos Nadler Gribel, DDS1 PLANAS DIRECT TRACKS IN Bruno Frazão Gribel, DDS2 YOUNG PATIENTS WITH CLASS II MALOCCLUSION

In Brazil, Class II malocclusions affect approximately one-third of children in the primary dentition period, and approximately two-thirds of the adolescent population. According to many authors, this type of malocclusion worsens with time, due to facial growth during childhood, both in terms of quantity and quality, and the facial pattern is established at an early age. The application of the Planas Direct Tracks concept and technique may represent an interesting tool for the correction and prevention of Class II malocclusion in an early treatment approach, working 24 hours a day, 7 days a week, applying oral functions and muscle activity to correct the malocclusion. World J Orthod 2005;6:355–368.

lass II malocclusion is a relatively sion are evident in the deciduous denti- Ccommon alteration of the stomatog- tion and persist into the mixed denti- nathic system in primary dentition. tion.” The interval considered during the According to da Silva,1 33.68% of chil- Baccetti et al study averaged 2 years 6 dren in the primary dentition stage in months ± 9 months in duration, shows a the Bauru area of the state of São progressive worsening of the malocclu- Paulo, Brazil, have a Class II malocclusion, with the involvement of the max- sion. Commonly, deep overbite, illa, which may become prognathic in 1Continuous Education Program in Functional Orthopedics, Uberaba mandibular retrognathism, and Class II some individuals. University, Uberaba, MG, and malocclusion at the canine level accom- Another important consideration is CECOMP, Belo Horizonte, MG, pany Angle’s designation of molar rela- the amount of facial and mandibular Brazil. tionships. These percentages are worse growth that occurs during childhood 2 Private practice of Orthodontics, in the late-mixed dentition stage, and (Table 1). According to Nanda,4 “The Belo Horizonte, Brazil. are likely associated with a Class II evo- pattern of development in each facial CORRESPONDENCE lution from Class I occlusions with a form is established at a very early age, Marcos N. Gribel, DDS flush terminal plane, as pointed out by even before the eruption of the first per- Av. Carandaí, 161 - 2nd floor van der Linden et al.2 manent molars and long before the ado- 30.130-060. Belo Horizonte, MG 3 Brazil As stated by Baccetti et al in 1997, lescent growth spurt.” This may explain E-mail: [email protected] “…the results of this study indicate that why the clinician does not see facial www.marcosgribel.com.br the clinical signs of Class II malocclu- pattern changes during adolescence.

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change of the mandibular posture. New Table 1 Linear growth measurements (mm) from 1 to 18 years of age bone formation at the head of the condyle and mandibular fossa of tempo- Cranial base Maxilla Mandible Age (N-S) (ANS-PNS) (Ar-Gn) ral bone has been observed. When restriction of maxillary growth is added, 1 55.0 38.8 71.0 overall dentofacial orthopedic contribu- 3 61.1 43.2 81.5 6 64.7 47.0 90.0 tion is approximately 70% and orthodon- 9 67.2 50.2 97.0 tic (dental) contribution is approximately 12 69.6 53.0 103.0 30%. Voudouris14 concluded, “The poten- 18 72.8 56.8 115.0 tial for condylar growth in juvenile nonhu- Data from Broadbent7 (Gribel6). man primates in the mixed dentition to induce increased mandibular length Snodell et al5 showed in 1993 that “At appears to be great.” 6 years of age, the transverse dimensions Figures 1 to 6 show an interesting had a greater percentage of the adult size demonstration of these experimental completed than the vertical measure- facts in humans. At 6 years of age, a girl ments for both males and females. All the had a bicycle accident and fractured the transverse measurements were over 80% right condylar head of the mandible. complete in growth by age 6 years when Nearly 3 years later, the oral surgeon rec- using age 18 years as 100%, with the ommended an orthopedic evaluation, exception of nasal width for males, which because the mandible started showing a was only 75% complete.” Gribel6 applied lateral shift and there was facial asym- the same methodology to 3 different lon- metry, which can be seen in the gitudinal series (Broadbent,7 Bathia and panoramic and lateral radiographs (see Leighton,8 and Martins et al9), and Figs 1 and 2). At this point, the head of reported that not only 80% of transversal the mandible showed the “bifid head of growth is present in a child 6 years of age, the mandible” (bifid condyle) aspect. but also 80% in the longitudinal aspect, After 2 years 9 months of treatment, with including the cranial base, maxilla, and a series of functional appliances, start- mandible (Table 1). ing with a Bimler A1, substituted 6 It is interesting to see from values in months later with a Simões Network 1, Table 1 (data from Broadbent7) that, at 1 and finally Indirect Simple Planas Tracks year of age, there is more than half with laterally inclined tracks, interesting (68.3%) of the adult horizontal compo- adaptations were observable, both in the nent of the maxilla (ANS-PNS) and 61.7% condyle of the mandible and the of the adult mandibular diagonal length mandibular fossae of the temporal bone (Ar-Gn). (the cranial base). The posttreatment The effects of mandibular change of radiograph (see Fig 3) shows only 1 con- posture are well established in the litera- tour of bilateral structures (orbits, key ture. In the 1970s, the Petrovic et al10,11 ridge, great wings of sphenoid, and servo-system facial growth theory started mandibular borders), suggesting a cor- a new era in terms of methodology. More rection of the asymmetry. Observe that recently, Fuentes et al12,13 have shown not only 2 mandibular heads are present that after advancing the mandible with a at the right temporomandibular joint functional appliance, not only are there (TMJ) (see Figs 4 to 6), but there are also increases in the condylar cartilage thick- 2 mandibular fossae (1 medial, the other ness as well as in the number of dividing lateral). Both fossae are at a lower cells at the mitotic compartment, there height, compared with the left TMJ. This are also important effects on gene indicates that the top of the mandibular expression in the condylar cartilage, fol- fossa of temporal bone had remodeled lowing the lateral functional shift of the downward, toward the 2 heads of the mandible. Voudouris et al14–16 and mandible.14–16 It seems that these modi- DeGroote17 demonstrated that just as fications at the TMJ level occur not only the growth of the mandible is affected, in nonhuman primates, as Ruf and other areas are also influenced by the Pancherz have shown with TMJ MRIs. 18

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Fig 1 (above) Pretreatment panoramic radiograph. Fig 2 (right) Pretreatment lateral radiograph showing 2 mandibular borders.

Fig 3 (left) Lateral radiograph showing bilateral structures superimposed, without double contours, even at mandibular lower and posterior borders, demon- strating the correction of mandibular asymmetry, 5 years after functional appliance removal, without any retainer.

Fig 4 (right) Three-dimensional recon- struction, showing bifid right condyle, 6 years after treatment.

Fig 5 (left) Computerized tomograph, coronal view, showing 2 fossae and 2 heads of the condyle in the right TMJ, both below left TMJ level, demonstrat- ing remodeling at the right fossa level, after treatment with a series of functional appliances.

Fig 6 (right) Magnetic resonance image, coronal view, 7 years after treatment, corroborates findings shown in Fig 5.

Figures 1 to 6 are from a previously pub- and if it is possible to moderate the lished case report that demonstrated amount of growth of the mandible and TMJ plasticity.19 The initial mandibular mandibular fossa of the temporal shift and facial asymmetry were cor- bone,10,11,14–19 then it may be possible to rected by means of modeling new bone interfere in, treat, and correct Class II and remodeling old structures. malocclusions during the primary denti- During childhood there is a great tion period, in time to affect the facial intensity and velocity of facial growth,5,6 pattern.4

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PLANAS DIRECT TRACKS stimuli. Proper respiration, mastication, TECHNIQUE swallowing, head and neck posture, and good oral habits may also affect the deci- The Planas Direct Tracks (PDT) technique sion-making process and the selection of represents an interesting early treatment the PDT procedure. approach to correct and prevent Class II Pedro Planas21 developed his tech- malocclusion. Patient compliance is a nique of direct tracks in the early 1970s. treatment concern when using functional At that time, the tracks were made of orthopedics with removable appliances, Adaptic. Today, photoactivated (light- even though young patients are easier to cured) composite resins may be easily influence and to obtain cooperation from attached to the primary dentition. There than adolescents.20 This concern applies is no specific indication for a particular with any kind of removable gear, such as composite resin brand, but it must have elastics, headgear, facial mask, etc. some resistance to allow for occlusal Since PDT are “glued” to the teeth, they forces during swallowing and mastication. work 24 hours a day, 7 days a week. Placement of PDT involves prophylaxis According to Voudouris et al,16 “Fixed of the enamel surfaces, followed by etch- functional appliances produce consistent ing of the occlusal surfaces. The adhesive and reproducible head of the mandible- is applied to the conditioned surfaces and fossa changes compared with the incon- then light cured. Small amounts of resin sistent results reported in the literature are then applied over the selected teeth, for removable functional appliances.” building an inclined plane to advance the Further investigation may corroborate mandible during closure of the mouth, these findings with PDT therapy. It has swallowing, mastication, and speech. It is been postulated that these fixed func- important to build individualized tracks tional appliances are more efficient over each tooth, to allow normal periodon- because they maintain the change of the tal physiology and stimulation. The Class mandibular posture at all times, includ- II direct tracks show, at the beginning, a ing during mastication. Planas,21 flat shape over the occlusal surface of the Simões,22 and Hylander23 have demon- posterior maxillary primary molar, parallel strated the important role of mastication to the occlusal plane. This allows an ini- in modeling and remodeling of the stom- tial increase of posterior vertical dimen- atognathic system. Occasionally, in some sion, unlocking the occlusion and, there- patients, during some periods of the fore, providing the mandible with more treatment, it is necessary to complement space to start moving laterally and PDT action with an appliance or myother- anteroposteriorly. After a short period, apy to improve tongue, lip, cheek, and approximately 1 month, more resin is facial muscle activity. added to the occlusal surfaces of the Diagnosis is an essential step in any posterior teeth, and a triangular profile kind of treatment. Cephalometric analyses and a prism shape is obtained (Fig 7). are often not available for this stage of The criteria to identify which teeth will be development. Facial proportions and max- selected to receive the tracks depends illomandibular relationships are therefore upon diagnosis and treatment planning, obtained by facial analysis. Dental casts and includes vertical dimension, tooth and direct examination of the patient may eruption, developmental stage of the provide good information in terms of care- occlusion and eruption, and adequate ful planning. Planas symptomatologic stimulation needs. In some mixed-denti- gnathostatic and calcographic diagnosis is tion patients, it is possible to apply PDT to effective in determining mandibular devia- the second primary molars. In this situa- tion, asymmetries, and underdeveloped tion, first molar eruption will provide an dental arches even in young children.21,22 increase in posterior vertical dimension, A functional evaluation of the patient’s both at the occlusal plane and the stomatognathic system, general health mandibular ramus, depending on the (respiratory alterations, postural changes) facial type (see case 2). may help to identify the need for adequate

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Fig 7 (a) Lateral view of Planas Direct Tracks (PDT) on the mandibular molar (triangular profile). (b) Frontal view of PDT on mandibular molar (prism shape). (c) Occlusal view of PDT on mandibular molar (prism shape). (d) Frontal view of PDT on maxillary molar (prism shape). (e) Lateral view of PDT on maxillary molar (triangular profile).

CASE 1 of the lateral pterygoid muscles have to work harder to keep and sustain the LAG was a girl, 4 years 11 months of age, mandible in a more forward position. with a Class II malocclusion, retrognathic When teeth contact, muscle spindles also mandible, and deep bite. These findings will be stimulated. Whenever the are discernable both in radiographs and mandible moves, TMJ receptors types I photographs (Fig 8). Almost all patients and II, originated from the primary neu- with Class II malocclusions at this age rons of the trigeminal mesencephalic also have retrognathic mandibles. Figure nucleus (as are muscle spindles and 9 shows the inclined planes of PDT. This Ruffini-like mechanoreceptors of the peri- is a modification of Planas’ original proce- odontal ligament) are stimulated. All dure.21 The tracks can be made directly these stimuli are consequences of the over patient’s teeth or in an indirect way, mandibular change of posture, and affect as described by Brandão.24 The main the neuromuscular response of muscles objective is to change the mandibular innervated by trigeminal, facial, glos- posture. The tracks act as interferences sopharyngeal, vagus, hypoglossal, acces- in the normal closing path. The Ruffini- sory, and cervical nerves (C1, C2, C3, and like mechanoreceptors—originated from C4); this effect normally happens during the primary neurons of the mesen- swallowing and mastication. All these cephalic trigeminal nucleus—detect the movements result in incremental blood new occlusal contacts and command the flow increase at the TMJ. Growth factors trigeminal motor neurons to fire and acti- arrive at the condylar cartilage and proba- vate the main protrusive muscle of the bly exert influence in the number of mandible, the inferior head of the lateral mitotic cells and thickness of the condy- pterygoid muscles. Unless there is rigid lar cartilage, as has been observed in fixation of the mandible, the inferior head adult animals.25 The movement at the

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Fig 8 Case 1. Retrognathic mandible, Class II molar and canine relationships, deep bite, “gummy” smile.

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Fig 9 Occlusal views of PDT, placed on primary first molars (maxillary and mandibular).

TMJ may produce a “pump-like The clinician does not have to pull or effect”.10,13,14–17 This theoretical model is push teeth to make things happen; most in accordance with the Petrovic et al10 of the time, the clinician must only servo-system theory and the modus permit or stimulate things to occur. As operandi of functional appliances proposed by Planas, in his Laws of described by Simoes, Petrovic, and Stutz- Development, the stimulation of 1 tooth mann in 1992.26 produces the eruption of the teeth that The hypothesis of lateral pterygoid belong to the same group: there are muscle inferior head hyperactivity is 2 groups in the mandible (each hemi- probably valid only for those procedures arch) and 3 groups in the maxilla that stimulate mandibular advancement (1 anterior group, the maxillary incisors; in an active way (such as Planas Direct and 2 posterior groups, including the and Indirect Tracks, Simões Network 1, canines, premolars, and molars from MARA, twin block), rather than for those each side). This is probably related to that keep and sustain the mandible in a the different embryologic origins of forward position in a passive manner, these components. such as achieved with rigid activators (ie, After 6 months, the mandibular retrog- Bionator, Harvold-Woodside, Fränkel, nathism and the lateral open bite have Bimler, Herbst and its variations). This resolved, due to teeth eruption (Fig 10). may explain why some authors have The Class II malocclusion and anterior encountered a decrease in pterygoid deep bite also have been corrected. The activity when using activator-like func- Class II PDT were kept in place for an tional appliances instead of an increase additional 2 months to ensure the stabi- in its activity. lization of all aspects involved (func- After Class II PDT are applied to the tional, neuromuscular, articular, skeletal, primary first molars, one normally will dentoalveolar, etc). After that, they were see a lateral open bite in Class II deep progressively removed by gently grinding bite patients in the primary dentition (see the resin. This procedure will allow pri- Fig 9). This will be corrected within a few mary first molars to erupt to the occlusal months by facial growth and tooth erup- plane level. Figure 10 shows normaliza- tion. The continuous tooth eruption in pri- tion of occlusion and of facial propor- mates and the 5 stages of eruption are tions, both in soft and hard tissues, after well explained in the literature by many 6 months. The 9-month follow-up views authors.27 Tooth eruption is a natural suggest normal development of the phenomenon that should be taken into occlusion, including a reduction of the consideration during treatment planning. “gummy” smile (Fig 11).

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Fig 10 Case 1. After 6 months, the malocclusion is corrected, allowing normal development of the stomatognathic system. Lip exercises are often required to stimulate proper lip posture and to discourage mouth breathing.

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Fig 11 Case 1. Views at 9 months posttreatment, showing normal development of the occlusion. Lip exercises may still be necessary.

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CASE 2 mal development, if normal form and function are obtained early. The same This girl, JKA, 6 years of age, had a maloc- approach is valid for any kind of preven- clusion similar to that of case 1, with a tive procedure: the inoculation of a vac- Class II malocclusion, deep bite, retrog- cine does not mean 100% protection; nathic mandible, and some “gummy” periodic visits to a dentist cannot guar- smile (Fig 12). However, her first molars antee that a patient will not develop were already erupting. In such a case, the caries. However, if a patient, parents, primary second molar is selected to and clinician adopt prevention in a seri- receive Class II PDT. Seven months later, ous manner, by watching over nutrition, the malocclusion was corrected in all 3 breathing, etc, not only the occlusion, but planes. Note that in the initial views, the the face and general health may be patient showed an inverted curve of Spee improved, thus avoiding or minimizing in the maxilla. In cases like this, it is wise later interventions. to supplement the Class II PDT action with We can treat malocclusions at almost a functional appliance for night-time use any age at the beginning of the third mil- and, if possible, a few hours each day. If lennium. The same is true for caries: we children are undergoing language training, can prevent caries with educational atti- use of the appliance during the school day tudes and supervision; remove carious is not recommended. An Equiplan, devel- lesions when superficial (enamel oped also by Pedro Planas, may stimulate involved); remove them with some anes- posterior teeth to erupt, and control the thesia (dentin involved); do endodontic eruption of maxillary and/or mandibular treatment if the pulp is involved; or incisors, depending upon the placement extract the tooth. In any case, the dis- of this stainless steel plate. The Equiplan ease is treated and the patient is cured. may help to control and reduce a Are malocclusions the only health prob- “gummy” smile during this stage of devel- lem that one should observe getting opment. Figure 13 shows the evolution of worse and then interfere? the treatment (total active treatment time, Even the best orthodontists in the 7 months). For the following 7 months, the world have altered their approach during appliance was used only at night, as a the course of their careers. Charles Tweed, retainer; during this time, the Class II PDT often called the world’s greatest orthodon- were ground to allow the primary second tist, produced outstanding results with full- molars to erupt. Figure 14 shows the nor- banded appliances in the permanent den- mal development of the occlusion 24 tition. But toward the end of his career, he months posttreatment. stressed that mixed-dentition therapy was Periodic follow-up visits will proceed vital, and he accepted only mixed-denti- throughout adolescence and young tion cases in his practice. Tweed wrote, adulthood. This periodic observation, 2 “As we learn more about growth and its to 4 times a year, assures the possibility potentials, more about influences of func- of intervention if anything deviates from tion on the developing denture, and more “normal” development, including detec- about normal mesiodistal position of the tion or control of any sort of deleterious denture in its relation to basal jawbones habits, altered functions, or disturbances and head structures, we will acquire a bet- in tooth eruption. In addition, this is a ter understanding of when and how to powerful public relations tool, since par- intervene in the guidance of growth ents will mention the care of their child’s processes so that Nature may better dental and oral health. approximate her growth plan for the indi- vidual patient. In other words, knowledge will gradually replace harsh mechanics, DISCUSSION and in the not-too-distant future the vast majority of orthodontic treatment will be With very early treatment, a second carried out during the mixed dentition phase of treatment may not be neces- period of growth and development and sary.28 There is a good chance for nor- prior to the difficult age of adolescence.”29

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Fig 12 Case 2. Pretreatment views showing retrognathic mandible, Class II molar and canine relationships, deep bite, and inverted curve of Spee in the maxilla.

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Fig 13 Case 2. After 7 months, the malocclusion is corrected, allowing normal development of the stomatognathic system. Note eruption of first permanent molars and leveling of the occlusal plane.

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Fig 14 Case 2. Note eruption of second primary molars, 6 months after PDT removal.

We surely know much more today30 6. Gribel MN. Avaliação quantitativa e qualitativa than 40 years ago. Why don’t we take a do Crescimento Craniofacial em crianças até os seis anos de idade. Rev Dental Press step further? 1999;4:19–36. 7. Broadbent BH Sr. Bolton Standards of Dentofa- cial Development Growth (ed 1). St Louis: REFERENCES Mosby, 1975:153–161. 8. Bathia SN, Leighton BC. A Manual of Facial Growth (ed 1). Oxford: Oxford University Press, 1. Da Silva OG. Estudo epidemiológico das más 1993:40–81. oclusões no Brasil. Rev Soc Paulista Orto 9. Martins DR. Atlas de crescimento craniofacial Ortoped Func Maxi 2002;55:22–33. (ed 1). São Paulo: Liv Ed Santos, 1998: 2. van der Linden FPGM, Radlanski RJ, McNa- 80–156. mara JA Jr. Normal Development of the Occlu- 10. Petrovic AG, Stutzmann JJ, Oudet CL. Control sion (video). Berlin: Dentaurum/Quintessenz. processes in the postnatal growth of the condy- MedLive, 2000. lar cartilage in the mandible. In: McNamara JA Jr 3. Baccetti T, Franchi L, McNamara JA Jr, Tollaro I. (ed). Determinants of Mandibular Form and Early dentofacial features of Class II malocclu- Growth. Monograph 5, Craniofacial Growth sion: A longitudinal study from the deciduous Series. Ann Arbor: Center for Human Growth and through the mixed dentition. Am J Orthod Development, University of Michigan, 1975. Dentofacial Orthop 1997;111:502–509. 11. Petrovic AG, Stutzmann JJ, Oudet CL. In: Graber 4. Nanda RS. Patterns of vertical growth in the TM, Rakosi T, Petrovic AG (eds). Dentofacial face. Am J Orthod Dentofacial Orthop 1988;93: Orthopedics with Functional Appliances (ed 2). 103–116. Saint Louis: Mosby, 1997:3–63. 5. Snodell SF, Nanda RM, Currier GF. A longitudinal cephalometric study of transverse and vertical craniofacial growth. Am J Orthod Dentofa- cial Orthop 1993;104:471–483.

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