Clark: Twin Block Functional Therapy: Applications in Dentofacial Orthopaedics, 2nd edition (2002)
Twin Block Functional Therapy: Applications inDentofacial Orthopaedics
WILLIAM J. CLARK, BS, DDO
2nd edition. 384 pages. 1,344 illustrations. $160. 2002.
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As the author insightfullypoints out in the preface tothis book, there are two greatcontroversies in theoretical orthodonticsthat were left unresolvedat the end of the 20th century.The first is the endless extractionvs. nonextraction debate--from the heated battles ofAngle and Case around the turnof the previous century, throughthe mid-century extractionistphilosophies of Tweed andBegg, to the current populist-basedanti-extractionism.
The second unresolvedcontroversy centers around functionalappliances and their abilityto address growth discrepanciesbetween the two jaws. Putotherwise, the question iswhether non-surgical dentofacialorthopedics as a means ofgrowth modification is a viabletreatment option.
In the first edition of TwinBlock Functional Therapy, WilliamClark presented a user-friendly,highly adaptable, removablefunctional appliance--the twin block--that seemed capable,through a number of possiblevariations, of correctingskeletal discrepancies in all threeplanes of space. In this secondedition, Dr. Clark elaborates furtheron the myriad clinical applicationsof his versatile appliance,while providing a wealthof references from reputable orthodonticjournals to support theorthopedic nature of functionalappliance therapy.
Dr. Clark presents caseafter case beautifully illustratingapplications of the twin block,from Class II, division 1 malocclusionswith deep overbites toClass III therapy, managementof crowding, adult treatment,and TMJ pain relief. He alsocovers two relatively new appliances,the Concorde facebowand the trombone appliance. Theformer is a modification of thedecades-old Kloehn facebowwith the addition of a labial hookthat allows for the attachment ofan elastic to the lower member ofthe twin block, with the aim ofrestricting maxillary growthwhile encouraging mandibularforward growth. The Concordefacebow is worn primarily atnight, thus solving a minor shortcomingof the twin block--disclusionwhile the patient sleeps.The author adds discreetly,"Patient comfort and acceptanceis similar to a conventional facebow."
The trombone appliance isa fixed arch-development appliance,the heart of which is alength of silicone tubing, activatedby an inner tube that slidesfreely within an outer tube "withthe facility to extend or contractthe length of the appliance". Thisdevice serves mainly to flare theincisors when deemed desirable.
Overall, this text is extraordinary.The author's systematicapproach to cephalometrics, patientexamination, diagnosis, andtreatment planning alone justifiesthe price of the book. Thecopious full-color illustrationsare outstanding. In addition toproviding a remarkable range ofclinical applicability, the authoralso provides some down-to-earthphilosophy with regard tothe use of statistics, evidence-baseddecision making, and thefuture of orthodontics. I was especiallyenamored of his comparisonof orthodontics to thegame of chess. As seen throughDr. Clark's eyes, the analogy ishighly appropriate.