IJOI Vol. 35
CBCT Imaging to Diagnose and Correct the Failure of Maxillary Arch Retraction with IZC Screw Anchorage
Lin JJ, Roberts WE
Abstract
All IZC mini-screws described in this report are made of stainless steel (SS) and are 2mm in diameter. The original preference was for 2mm x 12mm SS screws for both IZC 6 & IZC 7 applications. CBCT imaging has shown that the tip of the 12mm screws may contact the molar roots prevent retraction of the entire maxillary arch. An 8mm screw in the IZC is usually adequate for osseous anchorage, and the shorter screw is less likely to impinge on molar roots. Evaluating bone screw contact with molar roots via CBCT presents special problems for interpreting images. Scattering, distortion and beam hardening prevent clear, realistic images in 3D. Creating a 3D reconstruction of the molar(s) and screw, from a CBCT (0.25mm voxel) using the ITK-SNAP® (http://www.itksnap.org/pmwiki/pmwiki.php) software, produces images that are much easier to interpret.1 The IZC 7 site is a more suitable and safe location for screw placement because the buccal bone plate is thicker, compared to the IZC 6 site. When using IZC screws for anchorage to retract the maxillary arch, regular monitoring of progress is essential. If maxillary arch retraction is slow or arrested, CBCT imaging is indicated. If there is root interference, remove the IZC screw and replace it with a shorter screw in another location, as indicated. (Int I Ortho Implantol 2014;35:4-17)
Class III with Multiple Gingival Recession: Vestibular Incision Subperiosteal Tunnel Access (VISTA) and Platelet-Derived Growth Factor BB
Chen CK, Chang CH, Roberts WE
Abstract
Gingival recession can result in pain, hypersensitivity, root caries and esthetic concerns. There are many therapeutic options are available for treatment of gingival recession defects. This case report presents a novel treatment strategy of an acquired class III malocclusion in an adult male that was associated with upper anterior multiple gingival recessions. Access to the surgical site is obtained by means of an approach referred to as vestibular incision subperiosteal tunnel access (VISTA). VISTA is introduced by recombinant human platelet-derived growth factor BB saturated onto a matrix of beta–tricalcium phosphate with connective tissue grafts and a resorbable collagen membrane for root dehiscences. Such novel method lead to better wound healing by promoting primary wound coverage, better blood supply, easier clot stability and space maintenance with less scar formation. Connective tissue procedures and guided tissue regeneration-based root coverage are developed in an attempt to overcome clinical limitations while providing comparable result. In this case report, VISTA is a reliable method for use in root coverage procedures with long-term follow-up. (Int I Ortho Implantol 2014;35:22-36)
Key words: VISTA, gingival recession, root coverage, connective tissue graft, gingival surgery.
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Bimaxillary Protrusion and Gummy Smile Corrected with Extractions, Bone Screws and Crown Lengthening
Lin C, Wu Y, Chang CH, Roberts WE
Abstract
This case report describes the interdisciplinary treatment of a 25-year-old woman presenting with chief complaints of bimaxillary protrusion and excessive gingival display (“gummy smile”). She was dissatisfled with her previous non-extraction orthodontic treatment, rendered at age 10. The Discrepancy index (DI) for this severe malocclusion was 21. Orthodontic treatment involved extraction of four premolars to correct protrusion, and skeletal anchorage via four minisscrews (2 anterior and 2 posterior) to intrude the entire maxillary arch. Space closure utilizing maxillary extra-alveolar (E-A) bone screws reduced lip protrusion and the anterior miniscrews were used to intrude the maxillary incisors. Following orthodontics, surgical crown lengthening was performed in the maxillary anterior segment. 32 months of interdisciplinary treatment resulted in a near ideal result as evidenced by a Cast-Radiograph Score (CRE) of 15 and Pink & White (dental esthetic) score of 3. (Int I Ortho Implantol 2014;35:40-60)
Key words:Class I malocclusion, bimaxillary protrusion, surgical crown lengthening, self-ligating appliance, gummy smile
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Crowded Class II Division 2 Malocclusion with Class I Molars Due to Blocked In Lower Second Premolars
Shu PW, Yeh HY, Chang CH, Roberts WE
Abstract
An 18y2mo female presented a Class II Division 2 malocclusion associated with typical dental alignment problems: retroclined upper central incisors, labially flared maxillary lateral incisors, deep overbite, and severe crowding. Skeletally the malocclusion was complicated by a retrognathic mandible (ANB of 9°) steep mandibular plane angle (MPA 34°) and severe facial convexity (24°). Despite the Class II/2 pattern, the molars were Class I due to ectopic eruption and mesial migration of the mandibular rst molars, which resulted in the second premolars being blocked out. The Discrepancy Index (DI) was 37. Treatment mechanics were passive self-ligating brackets, early light short elastics (ELSE), anterior bite turbos, and extra-alveolar (E-A) miniscrews in the infrazygomatic crests to retract the entire maxillary arch. Nonextraction treatment for 32 months resulted in an acceptable skeletal compromises (4° increase in the MPA and lower incisor to mandibular plane angle of 109°), but dental alignment was excellent, as documented with Cast-Radiograph (CRE) score of 22 and a Pink and White (P&W) dental esthetics score of 3. (Int I Ortho Implantol 2014;35:64-78 )
Key words: Class II division 2 malocclusion, self-ligating appliance, bite turbo, bone screw anchorage
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Non-extraction Treatment of Impinging Overbite with Severe Crowding and a Straight Profile
Lee SA, Chang CH, Roberts WE
Abstract
Non-extraction treatment is a challenging option for adults with severe crowding and a straight profile, particularly when complicated with an impinging deep overbite, and lingually inclined incisors in both arches. This multifactorial malocclusion with a Discrepancy Index (DI) of 14, was initiated treated with relatively simple mechanics: anterior and posterior bite turbos with early light and short Class II elastics (2 oz). Subsequently, lip protrusion was controlled with extra-alveolar (E-A) anchorage by retracting both arches with miniscrews placed in the infrazygomatic crests and mandibular buccal shelves. Progress records were assessed at 19 months to plan the nal stage of active treatment. Bite turbos, intermaxillary elastics, and E-A skeletal anchorage resulted in an excellent correction in 23 months, as documented by a Cast Radiograph Evaluation (CRE) of 19 as well as a Pink & White (P&W) dental esthetic score of 3. (Int I Ortho Implantol 2014;35:80-100)
Key words:Deep bite, palatal impingement, crowding, extra-alveolar miniscrews, osseous anchorage, whole arch distalization, infrazygomatic crests, buccal shelves
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