1GROWTH MODULATIONUSING FUNCTIONALAPPLIANCES -CEPHALOMETRICPREDICTORS OFSUCCESSFUL RESPONSEDr. Sharanya Ajit Kumar, Dr. K. SadashivaShetty, Dr. A.T. Prakash
Authors2Dr. Sharanya Ajit Kumar Dr. K. Sadashiva Shetty Dr. A.T. Prakash
Authors3 Dr. Sharanya Ajit Kumar, B.D.S, M.D.S, Senior Lecturer,Dept of Orthodontics and Dentofacial Orthopedics, ,Vydehi Institute of Dental Sciences & Research Centre,#82, E.P.I.P Area, Nallurahalli, Whitefield Bangalore -560066, Karnataka, IndiaEmail – firstname.lastname@example.org Dr. K. Sadashiva Shetty, M.D.S, Professor and Head,Dept of Orthodontics and Dentofacial Orthopedics, andPrincipal, Bapuji Dental College & Hospital, Davangere,Karnataka, India. Email- email@example.com Dr. A.T. Prakash, M.D.S, MOrth RCSEd, Reader, Dept ofOrthodontics and Dentofacial Orthopedics, Bapuji DentalCollege & Hospital, Davangere, Karnataka, India, Email-
INTRODUCTION Control and modification of growth of theskeletal structures of the craniofacialcomplex, Prominent but controversial area of interestand activity within the field of orthodonticssince its inception. Growth modulation : functionalappliances -topic of much debate. key factors to its success - correctdiagnosis, case selection, appliancedesign and patient co-operation.4
Selecting cases that will ensure a successful responseto functional appliance therapy remains a problembecause the treatment results are often variable andunpredictable. A treatment outcome that has been particularlyquestioned is the enhancement of mandibular growth. Differing responses due to the design of the appliances. different functional appliance designs act in dissimilar waysand are not directly comparable Individual differences in sensory and neuromuscular response5
6 Assuming that a patient is compliant, pre-treatment skeletal morphological factors areresponsible for a favourable or an unfavourabletreatment outcome. Categorizing cases according to the orthopedicresponse to treatment provides an opportunity forcomparing characteristics and identifying differencesbetween those that responded with a skeletal changeand those that did not.
OBJECTIVES To determine whether there are any skeletalmorphologic features evident on a pre-treatment lateralcephalogram that may be used to predict a successfulimprovement in the sagittal dental base relationshipduring functional appliance therapy in patients with aClass II skeletal pattern. To compare the treatment changes between caseswhich responded favorably to growth modulation usingfunctional appliances and those which did not.7
METHODOLOGY SOURCE OF DATA 24 patients with class II skeletal pattern treated withfunctional appliance therapy were selected for the study,from the Department of Orthodontics and DentofacialOrthopedics, Bapuji Dental College and Hospital,Davangere. Two sets of lateral cephalograms- Pre-treatment andPost-functional cephalograms were used for the study.8
CRITERIA FOR SELECTIONOF DATA Class II skeletal bases Growing patients treatedwith functional appliance toadvance the mandible –Twin Block or FrankelAppliance. All patients were compliant.9
METHOD OF COLLECTION OFDATA10 Pre-treatment and post-functional lateral cephalogramswere analyzed and the change in the ANB angle wasused to determine the skeletal response to treatment withfunctional appliance. Based on the change in the ANB angle the patients weredivided into two groups of 12 patients each: Group 1- 12 patients who demonstrated a change inANB angle of 4° or more were identified as theSkeletal group. Group 2- 12 patients who demonstrated a change inANB angle of 1° or less were identified as the NonSkeletal group.
2 parts of study11 Comparisons were made between the mean pre-treatment (T1) parameters of Group I (Skeletal) andGroup II (Non skeletal) to assess any pre-treatmentparameters which were significantly different betweenthe groups. Changes due to functional appliance therapy from pre-treatment (T1) to post-functional (T2) stage wasmeasured as T2-T1 in both Group I (Skeletal) and GroupII (Non skeletal). The mean changes seen in Group I(Skeletal) and Group II (Non skeletal) were thencompared to assess the difference between changesbrought about by growth modulation using functional
STATISTICAL ANALYSIS12 Descriptive data that included mean and standarddeviation values were calculated for the linear, angularand percentage parameters. Results were expressed as mean and Standarddeviation. Comparative statistical analysis of the databetween both groups was done using One WayAnalysis Of Variance (ANOVA) – F-TEST. A ‘P’ value of < 0.05 was set for statistical significance.
RESULTS17 Comparisons were made between the mean pre-treatment (T1) parameters of Group I (Skeletal) andGroup II (Non skeletal) to assess any pre-treatmentparameters which were significantly different between thegroups which may help in predicting the response togrowth modulation. Table 1 presents comparative data for the pretreatmentcephalometric measurements at the start of treatment(T1) for the two groups.
21 Changes due to functional appliance therapy from pre-treatment (T1) to post-functional (T2) stage wasmeasured as T2-T1 in both Group I (Skeletal) andGroup II (Non skeletal). The mean changes seen in Group I (Skeletal) andGroup II (Non skeletal) were then compared in Table 2to assess the difference between changes broughtabout by growth modulation using functional appliancesbetween both groups.
Discussion27 Comparison of ramus height (Cd-Go) between the 2groups at pre-treatment stage revealed no significantdifference. Thus the cases all had a short ramus at the start of treatment. But as a result of treatment the Cd-Go in the skeletalgroup increased a mean of 4.5 mm but in the nonskeletal the mean increase was only 1.9 mm. -statistically significant. - successful cases the ramusgrowth in the vertical direction contributes to correction.
28 In the skeletal group the overjet decreased to asignificant extent (6.5mm) compared to the non skeletalgroup (3.7mm). the decrease in overjet can be attributed partly to the forwardposition of the mandible in the skeletal group. The mean change in SNB in skeletal group was found tobe 3.8 +/- 1.9 deg and for non skeletal group was found tobe 1 +/- 0.9 deg. -statistically highly significant. Forthose who responded skeletally, there is a much greaterforward movement of B point.
29 The comparison of the SN-MnP values between thegroups at the pre- treatment stage showed that themean value of SN-MnP in the skeletal group was 30 degand for the non skeletal group was 34.4 deg. The difference was statistically significant. This was inagreement with studies by Pancherz and Franchi L.and Baccetti. They believed that the prognosis oftreating class II malocclusions is partly dependant onmandibular plane angle.
30 The mean pre-treatment value of basal plane angle inthe skeletal group was found to be 21.9 deg and for thenon skeletal group was found to be 25.3 deg. The difference was statistically significant. This alsogoes to prove that the skeletal group at the pre-treatment stage had more converging jaw bases whichreflect a more horizontal growth direction.
31 The mean value of Jarabak’s ratio in the skeletal groupwas found to be 67.2 % and for the non skeletal group wasfound to be 63.9 %. The difference was statisticallysignificant showing that at the pre-treatment stage theskeletal group had an increased PFH to AFH ratioindicating a more horizontal growth pattern compared tothe non skeletal group. The mean value of the change in Jarabak’s ratio in theskeletal group was found to be 2.6 % and for the nonskeletal group was found to be 0.3 %. The difference wasstatistically significant implying that in the skeletal groupa significant increase in the posterior facial height wasachieved compared to in the non-skeletal group.
Conclusion The pre-treatmentparameters whichrelated to a favourableresponse were low mandibular planeangle, low basal plane angle, high Jarabak’s ratio Also in those caseswhich respondedfavorably the changesseen were increase in Cd-Go, decrease in overjet, increase in SNB, increase in Jarabak’sratio32Pre treatment parameters Changes seen
Significance33 The significance of these results will only have clinicaluse if patients with high growth potential can beidentified at the start of treatment. Further work on a greater number of patients would berequired to attempt to relate mandibular variables tosuch successful outcomes, eventually allowing theproduction of an index for mandibular features forvarious age groups. This would give the most accurate prediction perhaps ofwhether or not growth modification with functionalappliances would be possible in any individual case.
SCOPE FOR FUTURE STUDY34 A prospective study could be planned with sample sizecategorized uniformly considering the gender. Increasing the sample size could facilitate moresubstantial results. A three dimensional representation like ComputedTomography (CT) scan could give better results and lesserrors. An index could be prepared to be used for caseselection for growth modulation.
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