Space Management - American Association Of

3/10/13Space Management in the Mixed DentitionDr. Steven DugoniDirector of Early Orthodontic TreatmentClinicUniversity of the PacificArthur A. DugoniSchool of DentistryAssociate Clinical Professor 1/2 day/wkPrivate practice for 30 yearsLecture Outline Arch length problems in the mixed dentitionArch length analyses for measuring crowdingPrevention and correction of crowding in themixed dentitionDevelopment of the dentition inthe mixed dentition Moorrees and Reed; J Dent Res 1965 Normal changes: age 8-13 years old Mn arch length decreases 2-3 mm Mn arch circumference decreases 3.5 - 4.5 mm “If crowding is present in the early mixed dentition it willnot improve with further growth and development” .butwill get worse especially in the Mn arch1

3/10/13Arch length changes from 6 week to 45 year Bishara et.al Angle Ortho 1998Arch length decreasefrom age 8-13 inuntreated patientsLoss of space and changes in the dental arch afterpremature loss of the lower first primary molar Kumari, J; Pedo Prev Dent - June 2006 Space loss in the mandible is mostly due todistal movement of primary cuspidThe erupting anterior incisors pushed theprimary cuspid towards the distal more thanthe erupting first permanent molar did onthe second primary molar towards themesial.Immediate and six-month space changesafter premature loss of a primarymaxillary first molar; Lin et al; JADA, Vol. 138, JADA, March 2007 distal drift of the primary canines toward the site ofthe extraction and palatal migration of the maxillaryincisors.use of a palatal arch to prevent palatal movement ofincisors may be more valuable than the use of bandand-loop space maintainers with regard to preservingthe existing dental arch.1 mm of space was lost, not clinically significanceto warrant use of a space maintainer.2

3/10/13Lin et al. JADA 3/07Effect of premature loss of deciduous molars Angle Ortho 1984; Northway et al; Premature loss of the maxillary primary first molar (MxD/D) before age 11 results in: Mx 6/6 and Mx E/E shift mesiallyMx C/C shift distallyMx 4/4 erupt more mesialMx 3/3 erupt labially and blocked outTraumatic injuries to the teeth Andreasen, F.; Andersson, L; 4th Edition 2007 Early loss of a primary incisor(s) as a result of caries ortrauma usually results in very little change in the dentitionSpace maintenance is not necessaryTeeth can be replaced using either a removable or fixedpartial denture for esthetic-social concerns3

3/10/13Premature Loss of LowerPrimary Cuspids Foley, T. F. , G. Z. Wright , and S. J. Weinberger .Management of lower incisor crowding in the early mixeddentition. ASDC J Dent Child 1996. 63:169–174.Proffit, W. R. Contemporary Orthodontics TextbookMoyers, R. E. Handbook of Orthodontics TextbookPremature Loss of LowerPrimary Cuspids Lingual positioning of the incisors, resulting in adecreased arch length and deepening of the biteEarly loss of primary canines required spacemaintainer to prevent lingual movement of theincisorsUnilateral loss of primary cuspidcauses a midline shiftArch length considerationss Is there crowding?s How much crowding?s When to treat? Now or later?s How to treat?4

3/10/13Lower Incisor Crowding in the Early Mixed DentitionHow to treat?s Expansions Hold leeway spaces Extraction of primary teeths Extract permanent teeth laterArch Length Analysiss Obtain accurate measurement of mandibularcrowdings To determine if needs treatments To determine if extraction or nonextraction caseArch Length Analysess Hixon-Oldfathers Johnston-Tanakas DirectThese analyses do not account for curve of spee,lower incisor position or facial profile5

3/10/13Arch Length Analyses Articles Bishara and Staley*, “Mixed Dentition Arch Length Analysis"AJODO 86: 130-135, 1984.Johnston and Tanaka, "The Prediction of the Size of UneruptedCuspids and Premolars.”JADA,88: 798-801, 1974Gardner, "A Comparison of Four Methods of Predicting Archlength”; AJO 1979;75: 387-98. ** Hixon-Oldfather most accurate analysis. Accurate to within 0.4mmHixon-Oldfather Arch Length Analysis6

3/10/13Arch Length essOKSpaceDeficientLeeway Spaces Maxillary0.9 mm per sides Mandibular 1.7 mm per sideRef- Dr. Hays NanceEvaluation of Dental Crowding Start with the mandibular archMandible is the “contained arch” Mn midline suture fuses at about one year of age and thusorthopedic expansion is not possible like it is in the Mx.Consider preservation of Leeway space for correction of crowding7

3/10/13Lingual arch in the mixed dentition toresolve crowding Gianelly, Brennan AJODO 1/00 107 consecutive patients- ave. 8.6 yrs. Soldered lingualarch from Mn 6ʼs to contact cingulum at Mn incisorsAverage crowding -4.85 mm ( /- 2.14mm). Adequatespace was available in 60% of the treated patientsLingual arch in the mixed dentition to resolve crowding Gianelly, Brennan; AJODO Jan 2000 “Crowding should be treated with arch length preservationfor the majority of patients” “Consider serial extraction rather than expansion for theremaining patients whoʼs crowding cannot be resolved byutilizing the leeway space”An Approach to Resolving MixedDentition Anterior Crowding Extract Mn Dʼs (or Cʼs) to borrowleeway spaceRemovable lingual archPlace lingual arch at contact area atincisal 1/3 of crown to controlrotationsAdjust LA during 1st 6 months tillincisors aligned, then leave passiveH.O. 0.5 mm8

3/10/13Lingual Arch Treatment No (or slight) forward pressure on lower incisorsNo (or minimal) expansion- hold leeway space is allmost cases requireIncrease in arch perimeter due toorthodontic expansionAJODO 1991 Germane et.al.A mathematical model to study changes in archperimeter. Molar expansion is least effective in gainingarch perimeter. 5 mm expansion 1.5mm increase in arch perimeterCanine expansion of 1mm provides 0.73 mmof space to correct incisor positionCanine expansion and incisor advancementis most effective in gaining arch perimeter.Mandibular arch length increase during mixeddentition treatment - postretention evaluation ofstability and relapseLittle, Riedel, and Stein, AJODO 1990 Cases tx with fixed edgewise appliances, activelingual arches, lip bumpers, or removableappliances."These enlargement method of treatmentrevealed the poorest stability resultscompared to their other studies of Mnincisor stability.”9

3/10/13Early mixed dentition treatment - postretention evaluationof stability and relapse Dugoni, Lee, Varela, Angle Ortho 1995 25 patients treated with a lower lingual arch in the earlymixed dentition Removable- adjustable lingual arch 3 mm or greater incisor crowding Most had extraction of Mn D/DEarly mixed dentition treatment - postretention evaluationof stability and relapse Dugoni, Lee, Varela, Angle Ortho 1995 Measured irregularity index (IRI) at T1, T2, and T3 (approxage 8, 12 and 28)Mean 9.5 years post-retention recordsInitial mean IRI 7.8 mmAge 12 mean IRI 1.0 mm9 Yr retention mean IRI 2.6 mmEarly mixed dentition treatment - postretentionevaluation of stability and relapse Dugoni, Lee, Varela, Angle Ortho 1995 The lower incisor alignment was clinically acceptable in 76%of cases in the postretention stage. The lingual arch was effective in aligning the lower incisors atPhase II evaluation and reducing the crowding to a IRI indexclose to zero. The lower lingual arch could obtain ideal alignment of thelower incisors without incisor bonds and maintain thealignment by arch length preservation10

3/10/13Summary Normal arch dimension changes Space consideration with early loss ofprimary teeth Benefits an arch length analysis Treatment for early loss of primaryteeth and crowding11

Space ! Available! Compare! Space ! Required! Space! Excess! OK! Space! Deficient! Leeway Space!! Maxillary 0.9 mm per side!! Mandibular 1.7 mm per side! Ref- Dr. Hays Nance! Evaluation of Dental Crowding! Start with the mandibular arch! Mandible is the “contained arch”! Mn midline suture fuses at about one year of age and thusFile Size: 1MB