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1 S Strategies trategies for for optimal finishing optimal finishing Prepared by: Prepared by: Dr Mohammed Alruby Dr Mohammed Alruby يلعف ةدر يلع ينبساحتو كلعف يسنت نا يه هحاقولا S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
2 Finishing: is the last stage of active treatment and depend on the previous stage of treatment Finishing stage of treatment should be evaluated according to four major categories: 1-Intra-oral: -Inter arch: midline, and Bolton discrepancy -Intra arch: 1st order 2nd order 3rd order Curve of spee Curve of monson 2-Extra-oral: Smile arc Incisors display Gingival display Buccal corridor Incisal plane Midline Upper incisor third order angulation Tooth morphology 3-Radiographic 4-Functional: canine guidance, lateral excursion, anterior guidance 1-Intra-oral objectives: Intra-arch analysis: Each tooth must be evaluated with references to its 1st, 2nd ,3rd, order position: 1st order: -Tooth should have no rotation -Light inter-proximal contact -Cusp tip and fossa should follow the perfect arch form -Buccal surface of upper 1st molar should be parallel to the palatal suture -An occlusal mirror can be very useful to identify the minor rotation and bucco-lingual displacement of teeth outside the arch form 2nd order: -The marginal ridges should be at the same level particularly at the buccal segment -Root parallism should be well -In extraction cases, small degree of crown tipping will occur and root parallism will required, ----- also accentuating the distal tip in anterior region can help to decrease any excess space in anterior region 3rd order: -Is most relevant to inter-arch objectives (occlusal relationship) -A small curve of Monson between the buccal segment allow for proper occlusal function (adequate inter-cuspation without balancing interferences) -An accentuating curve of Monson results in balancing interferences -Achieve a gentle curve of spee from the anterior teeth to the posterior buccal segments S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
3 N: B: Curve of spee: = Anterior posterior curve, produced by F Grave Von Spee in 1890 = It is a line drown beginning at lower cusp teeth following the cusp tip of bicuspid and molars continuing as an arc through the condyle on either side = There is a reverse curve of spee in maxillary arch Curve of Wilson: = Side to side curve = When looking at a coronal section of mandibular dentition from the front ------ line tangent to the buccal and lingual cusps of mandibular posterior teeth bilaterally = concave in mandibular teeth and convex in maxillary arch = this curve helps on: -Make the teeth alignment parallel to the pull of direction of medial pterygoid which provides optimum resistance to masticatory force -The elevated buccal cusps prevent the slippage of food from the occlusal table during mastication Curve of Monson: = produced by Gs Monson 1920: three dimensional combinations of spee and Wilson = all cusps and incisal edges in a natural dentition are tangent to a surface of sphere approximately 4 inches (10.2m) in radius with its c Enter at the area of glabella = when viewed from the frontal plane, curve not exceed 5-10 degree from the horizontal plane = this curve obtained by extending the curve of spee and Wilson to all cusps and incisal edges Inter-arch analysis: = the 1st molars and canines are the most important teeth to evaluate the inter-occlusal relationship = the main objective to seat the canine in a class I relationship and obtain good coupling with the antagonist canines = this occlusal relationship is difficult to achieve if there is tooth size discrepancy (Bolton) = the upper lateral incisors and lower 2nd premolars are usually responsible for the discrepancy = there are two types of occlusion considered ideal: -Cusp to fossa -Cusp to interproximal space relationship = the lingual cusps in upper and buccal cusps in lower premolars should occlude in the interproximal space = in anterior segment, overbite and overjet are the most critical factor in achieving a proper inter- occlusal relationship More than 50% overbite may be excessive, as the contact of the lower incisors on the lingual surface of upper incisors in these patients would not be on the cingulum It is important that lingual surface of upper incisors be properly inclined to allow the lower incisors to slide anteriorly The inter canine and molar widths should be coordinated to prevent excessive buccal overjet or buccal cross bite tendency = midlines are also used to evaluate inter-occlusal relationship, any discrepancy more than 2mm should be addressed during the previous phases of treatment. A discrepancy of 1-2mm or more between the midlines is usually due to tooth size discrepancy and will probably result in an inadequate occlusal relationship S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
4 2-Extra-oral objectives: The extra-oral objectives are based on esthetic concept: the key factors within the smile arc: a-Smile arc: In the finishing stage, little can be done to significantly affect the smile arc Small finishing bends can use to extrude or intrude the anterior teeth Avoid finishing with less than 50% overbite and flat or reversed smile arc b-Incisor display: = On average: female: 2-3mm of incisor showing at rest and 1mm of gingiva during smile = In cases of open bite with excessive incisor display = It is not unusual to find an open bite tendency still present at finishing phase of treatment = The overbite correction should be done by extruding the lower anterior teeth, which accomplished by accentuating the lower curve of spee c-Gingival display: = The amount and characteristic of the gingival display are important aspect to consider in a smile Males; do not show any gingival show during smile Females: 1mm gingival show during smile = incisal edges reflect the discrepancies in the gingival height provided that no incisal wear is present, and correction of incisal edges results in adequate gingival height = factors involved in the final incisal edge position: -Relationship of gingival height -Tooth proportion -Lip to tooth relationship -Crown / root ratio In young patient: the gingival margin usually follows the incisal edges of lower anterior teeth, this problem is corrected as the canines and the central incisors are levelled on the 1st stage of treatment In adults: wear facets can complicate the determination of where proper gingival height should be located As the incisors supra-erupt, good incisal edge relationship with canine will exist but a significant discrepancy in gingival height will developed, to correct this discrepancy you must do one of the: -Gingivectomy / crown lengthening with no restoration -Or gingivectomy / crown lengthening with restoration (composite, veneer, crown) -Or intrusion of four anterior teeth and restoration (composite, veneer, crown) The factor that control all these decisions is crown / root ratio N: B: Symmetry in the gingiva and proper gingival height relationship in the upper arch are important consideration during initial bracket positioning and final finishing During finishing, gingival display and symmetry can alter within range of approximately about 1mm by selective intrusion or extrusion on anterior teeth d-Buccal corridor: Space between the posterior teeth and corner of mouth during smile This space was eliminated by transverse maxillary expansion Broad arch more likely to fill space than narrow arch Moving maxilla forward will reduce the amount of corridor e-Incisal plane: The incisal cant can be the result of incorrect bracket positioning, a symmetry mechanics, or true maxillary skeletal that was undetected during diagnosis due to dental compensation. SO: differential diagnosis between dental and skeletal incisal cant is important. S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
5 = patient who have an incisal cant due to skeletally canted maxilla generally presented uneven heights between the labial commissures and occlusal surface of premolars = in patients where the cant involves only the anterior teeth, correction in the finishing stage are different but possible f-Midline: = A discrepancy between the upper and lower dental midlines is generally noticeable at the end of treatment, this problem was most difficult to correct at this stage. = To achieve coincident midline during finishing, the range of correction for each arch is approximately 1mm to each side = Tipping movement is the major type that used to correct midline at finishing stage = by correcting the incisal cant, the midline problem may be improved, it is important to consider all smile characteristic together, correction of one characteristic should maintain, if not improve the others. = using anterior cross elastics for correction of midline problem is useful but has some problems that should the orthodontist notice it as: long term use of vertical elastics in anterior segment may lead to canting the occlusal plane as a result of vertical component of elastics and also there is a rotation of dental arch around the Y axis that lead to buccal segment cross bite tendency and a Brodie bite tendency on the other. Brodie bite: Is a comparatively rare type of malocclusion found in primary and mixed dentition. It is affect chewing and muscle function, but also impairs normal growth and development of the mandible. g-Upper incisors –third –order inclination: = esthetic consideration of upper incisal inclination is important not only from the profile view but also from the frontal view = third –order tooth correction is difficult and time consuming movement = extensive bone remodeling needs to occurs as root correction and side effect as upper molar mesial migration become common. The best way to approach this objective is by maintaining a proper moment / force ratio during the retraction phase of extraction case. = care must be taken to prevent the incisors from flaring and this can achieve by cinching the arch wire Rowboat effect: Occurs with root correction: flaring of incisors and mesial tipping of molars Class II elastics is recommended to prevent this effect h-Tooth morphology: = Tooth morphology in the anterior segment or esthetic zone is of primary importance abnormal tooth morphology should be accomplished during diagnosis and treatment planning phase = in finishing phase, communication with the team is most important and will help to determine the finishing orthodontic tooth movements needed. = many restorative procedures should be done in conjunction with periodontal procedure to achieve best tooth proportions =-= Tooth proportions are influenced by the position of the gingival margin as well as the width and height of the tooth Examples: 1-Slight contouring of the incisal edges of upper anterior teeth especially canine are recommended at end of treatment of most patients 2-Incisal edge contouring after fracture is important after previous extrusion 3-Gingivectomy or crown lengthening procedure may be indicated if patient display gingiva on smiling S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
6 4-After canine substitution in cases of missing lateral, alteration of canine morphology to mimic lateral is important and usually done in early stage of treatment 5-The premolars that substitute canines also need to be contoured on the lingual cusps to avoid balancing interferences 6-The pronounced lingual fossa of the upper incisors, is abnormal crown morphology found most frequently in Asian and African population, so it is recommended to contour the fossa to achieve better posterior occlusion 3-Radiographic objectives: Just before starting the finishing stage of treatment, it is recommended that panoramic radiograph be taken for: 1-Evaluate root angulation and root parallelism 2-Problems in second –order angulation of upper lateral incisors, lower premolars and teeth adjacent to extraction sites 3-Evaluate root resorption, if external root resorption is observed, the orthodontist wants to decrease the length of time for finishing stage 4-Evidence of any deterioration in periodontal health and eruption angle of third molars 5-If orthodontic treatment is finished before complete eruption of 2nd molars Periapical radiograph: Are usually indicated only in finishing stage to obtain more detailed view such as extensive root resorption OR root parallelism adjacent to implant site OR periodontal bone loss N: B: Root parallelism is important because of: 1-Occlusal load of forces will transmit properly a cross the longitudinal axis of the tooth 2-If crown and root is not in proper position so there is a greater potential for relapse 3-There is a potential for periodontal problem due to root a proximity but this statement not supported by literature N: B: Root angulation problems observed in the finishing panoramic radiograph may related to abnormal morphology and / or bracket errors, this is especially in buccal segment, where it is difficult access for bracket placements 4-Functional objectives: = a proper functional occlusion is the goal in every orthodontic treatment = to achieve this ideal occlusion during the finishing stage it is important to have the maximum amount of normal occlusal contact during maximum inter-cuspation = coinciding centric relation with centric occlusion is important and small discrepancy between them is acceptable (long centric) With lateral movements of jaw, canine dis-occlusion is slandered, no balancing contact should be present. Canine dis-occlusion is also a major protective factors in patients who receive any type of anterior esthetic restorations (veneers, composite, porcelain crowns) During protrusive movements, the anterior teeth should dis-occlude the posterior teeth = all these movements should be evaluated during the finishing stage of treatment and proper adjustment in crown angulation = small adjustments, can be made after appliance removal can occur in occlusion by rotary instrument, and this should be minimal and limited amount of tooth structure removed S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
7 Over correction: Rotational correction: it is believed by some that over-correction of rotated teeth especially in anterior inferior segment of teeth, may be necessary for stability Vertical correction: over correction in cases such as open bite and deep bite cases, this process should begin during initial bracket placement and also can occurs in the finishing stage AS: bracket in anterior segment could be placed 0.5mm more gingival in cases with an open bite tendency and 0.5mm more incisal in deep bite cases. Unique finishing situation: 1-Lower incisor extraction: May introduce Bolton discrepancy if no tooth size discrepancy is present (excessive mass in lower arch) = the patient end treatment with class I canine with excessive overjet or ideal over bite with class III canine tendency = another problem observed is black triangle interproximal, slight interproximal reduction move the contact gingivally and decrease the black triangle size = decrease the inter-canine distance and an excessive canine overjet could occur 2-Finishing with primary teeth: In patient with retained molar deciduous, some advocated extraction of primary molars and close the space while other believe that primary molar should kept for long as possible and then restored with implant or bridge. 3-By passing debilitated teeth during finishing: After taking a finishing panoramic radiograph there may be evidence of localized root resorption so: - minimize the time spent on the finishing stage -By pass the affected tooth in order to avoid any force that can perpetuate the root resorption 4-Canine substitution of missing lateral incisors: = when canine replace lateral incisors, ideally the majority of canine contouring should have been accomplished in the early phase of treatment, but during finishing, only minor contouring should be done. = when premolars replacing canine, it has gingival height that is 1-1.5mm occlusal than canine and canine is usually at the same level of central incisors To achieve same gingival level canine should extrude approximately 0.5 to 1mm and for premolars replacing canine periodontal respective procedure, take care about exposure cementum during this procedure = lingual cusp of premolar replaced canine, this cusp should be reduced mainly for functional reasons to avoid balancing interferences during distocclusion, take care about remove excessive amount of tooth structure to avoid prospective sensitivity 5-Edentulous site for an implant = The maximum spaces for implant should approximately 6mm, the most common problem was the root angulation of the teeth adjacent to implant site = During finishing adequate moments for root correction should be placed in these adjacent teeth to achieve the minimum 6mm distance through the entire implant site S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
8 Interproximal reduction during finishing: Interproximal tooth reduction has been advocated where tooth size discrepancy exists—this procedure is used to achieve better occlusal relationship in the finishing stage Tooth size discrepancy should be evaluated during the diagnosis phase and to prevent long term sensitivity of tooth Finishing with class II mechanics: In class II mechanics using elastics or inter-arch appliance class II, the correction is achieved by rotating the occlusal plane in a clockwise direction. SO, torque is needed to be applied on the anterior teeth or apply buccal crown torque on the arch wire via additional bends or using springs that adds a moment to the teeth that will correct root angulation Finishing sequence = The buccolingual inclination of upper anterior segment is important in the finishing stage for occlusal and esthetic reasons = The bracket and wire are the major factors involved in achieving the proper anterior-superior inclination = Depending on the buccolingual inclination of the tooth and the relation of the bracket to occlusal plane 17X 25 beta titanium wire can be selected = Another option to increase the dimension of the rectangular wire in a Preadjusted bracket 21X25 in 22-inch slot bracket Or adding bends to the existing arch wire to create the couple = other option in patient loss third order control in the incisors by changing the slot from 0.022- inch slot to 0.018-inch slot in the anterior segment. Torque is affected significantly by arch wire dimension. = for additional third order correction on specific teeth 0.019 X0.025-inch beta titanium CAN is recommended = to achieve 2nd order objectives 0.016 X 0.022-inch beta titanium Or 0.016 X 0.022-inch steel wire can be used = to achieve good final inter-cuspation of the buccal segment, vertical elastics may be worn for short period of time, usually 2 -3 weeks Prolonged wear of elastics with light or no arch wire may result in deformation of the arch form and / or lingual inclination of the teeth S Strategies trategies for optimal finishing for optimal finishing Dr. Mohammed Alruby Dr. Mohammed Alruby
