Jumbo Separators for Partial Molar Impactions
Partial impactions of eruptingpermanent molars do notoccur often, but when they do,they can cause long-term problemssuch as disruption of theocclusal plane, damage to abutmentteeth, and creation of foodtraps with subsequent toothdecay and periodontal problems.A sequence of elastic separatorscan be used to resolve many ofthese impactions efficiently andeffectively, with minimal patientdiscomfort.
Conventional elastomericring separators come in twosizes: green--3mm diameter,.75mm thick; and blue--4mmdiameter, 1mm thick (Fig. 1).These are easy to fit and effectiveat moving teeth apart asmuch as 1mm.
What I call "jumbo separators"--larger and thicker, blackrubber "O" rings, 6mm diameterand 2mm thick--can be purchasedfrom rubber outlets orhydraulic supply companies. These can be sterilized in thesame way as with standard separators.The jumbo separatorsshould be soaked in hot water fortwo to three minutes prior to fitting.This makes them more pliableand less susceptible to fracture.
The standard separator plierstend to overstretch and partiallydeactivate the separators(Fig. 2). Although this is not aproblem in routine use, maximumactivation is required to uprightimpacted molars. In suchcases, therefore, the separatorsshould be placed with a pair offine, slim-line needle holders.Stretching the separator by nomore than one-third of its diameterallows easy placement withlittle distortion and deactivation.
When used in sequencewith the smaller orthodontic separators,the jumbo separators canmove teeth apart as much as2mm, which is often enough tofree partially impacted molars.
A 9-year-old female presentedwith an upper left firstmolar partially impacted into thedistal surface of the second deciduousmolar (Fig. 3). Becausepatients this young do not fullycomprehend the need to correctsuch impactions, treatmentneeds to be gentle and, where possible, to involve minimumpatient cooperation. Patients areasked to continue routine toothbrushing,but not to floss or usetoothpicks around the separators.
In this case, a blue separatorwas fitted in about oneminute, using slim-line needleholders, and left in place for oneweek. The blue separator wasthen replaced with a jumbo separator,requiring less than twominutes of chairtime. The blackseparator was left in place fortwo months to allow stabilizationof the correction. Patientdiscomfort was minimal duringthis treatment.
A review six weeks laterconfirmed that the impaction hadnot relapsed.
A 19-year-old male patienthad previously undergone orthodontictreatment involving theremoval of all second permanentmolars. The lower third molarserupted with a mesial tilt and becamepartially impacted into thedistal surfaces of the first permanentmolars (Fig. 4).
Blue separators wereplaced for one week, then replacedwith jumbo separators foranother two months. Total chairtimewas less than 10 minutes,and the patient experienced littlediscomfort.
Advantages of this serialseparation technique include: