Class III Malocclusion Camouflage using the Damon Q Self-ligating System :: A Summary Case Report
by Shadi Samawi
In my first blog post in 2016, I will be presenting a brief case report demonstrating the effectiveness of the proper use of a passive self-ligating system (Damon Q) in camouflage treatment of an adult with a malocclusion of considerable skeletal discrepancy, namely; Class III malocclusion in this particular case.
The patient was a young adult aged 20.5 years at the time of presentation, and was distressed by the “forward appearance of his lower jaw and teeth” as well as some functional annoyance due to what he described as “an uncomfortable bite”.
The patient presented with a Class III malocclusion and incisors relationship with full-unit Class III molar and canine relationships bilaterally. There was a reverse overjet (OJ) of 3-4mm upon full closure with no apparent mid-line shifts or deviations. The overbite (OB) upon closure was within average and the Lower Anterior Face Height (LAFH) was only mildly increased. There was a tendency for posterior crossbite (when in centric relation) with the upper right first molar in complete cross-bite with the lower arch.
The key finding was the presence of a forward mandibular displacement as the upper and lower incisors came into an edge-edge relationship upon closure in centric relation. This forward mandibular posture exaggerated the Class III appearance and was, indeed, a favorable finding in such a case as it indicated an improved chance for camouflage treatment.
Analysis & Discussion
The cephalometric analysis demonstrated a moderate skeletal Class III relationship with a clear, backward growth rotation pattern of the mandible. The presence of a forward mandibular displacement and an edge-to-edge incisor relationship in centric relation are favorable indicators for attempting camouflage in such cases. In addition, both the upper and lower incisors inclinations were favorable for attempted camouflage treatment. Full correction of the posterior crossbite of the upper right first molar could prove difficult to achieve, but would be attempted nevertheless. Any consideration for any surgical options, extractions or any kind of “complex” appliances and mechanics was deemed unnecessary and was also declined by the patient from the very beginning.
The decision was made to attempt camouflage using the Damon Q passive self-ligating appliance, with light Class III elastics and on a non-extraction basis.
Initial dis-occlusion would be done using anterior bite raising composites lingual to the lower central incisors, and light Class III “shorty” elastics (Quail) from the initial visit.
At a later stage, posterior crossbite correction of 16 would be attempted using cross-elastics (through-the-bite elastics) on the right side and a bonded button palatal to 16.
Some minor buildups of below-average width upper lateral incisors were deemed necessary post-debond.
Upper and lower permanent retention with canine-canine flat, braided bonded retainers were planned.
Summary of Treatment Progress
Treatment was started by direct bonding of Damon Q standard torque brackets on both upper and lower arches, including the lower 7s at this initial stage. Both upper 7s were bonded and engaged after a few visits. (My rationale for not selecting variable torques from the start is explained in a previous blog post about passive self ligation). Upper 0.013 CuNiti (Damon Archform) was used in the upper arch while in the lower arch, I preferred to use a standard Ovoid III 0.012 Niti, rather than the wider Damon archform. I often resort to this technique in Class III camouflage cases were expansion in the lower arch is not desirable nor needed. Light, Class III “shorty” elastics (Quail) were used between upper 4s and lower 3s from the first visit, with anterior bite raising composites lingual to lower central incisors for dis-occlusion.
The Class III incisor relationship persisted until 7-8 months into treatment, however once the upper 18×25 CuNiti arch was introduced and switched to full-time Class III (Moose) elastics, a positive overjet was achieved within a couple of months. This was further aided by full, lower Power-chain elastics (placed underneath the archwire to further reduce friction with the archwire). A direct-bond button was bonded palatal to 16 and therough-the-bite elastics (Zebra) were used to aid corrrection of the posterior crossbite on the right side, aided by some posterior expansion of the TMA archwire as well.
The final upper archwire was a 19×25 Damon Form TMA wire, with the lower being a 17×25 TMA. Class III Box elastics were used in the final stages to settle-in the occlusion bilaterally.
The total treatment time was approximately 21 months. Practically, all projected treatment goals were achieved in a comparatively reasonable treatment time-frame.
A truly “orthognathic” case cannot, most surely, ever be turned into a “non-orthognathic” case under any circumstances, however, clinically-speaking and for all practical considerations, self-ligating systems – when properly used – seem to be much more efficient at performing certain tooth movements than conventional fixed appliances, and thus are extremely useful in such “borderline” cases, as in this case.
This case demonstrates the broad range of possibility for camouflage treatment in adult, borderline Class III malocclusion cases using the low friction and relative efficiency of self ligating systems, and with minimal, or – as in this case – no use of auxiliary appliances. This, of course, should by no means be interpreted as “evidence” in and by itself, however, such treatments have been consistently demonstrated in many similar situations, and by many – and more able – practitioners and even more difficult malocclusions – and as such, it should be taken as merely a demonstration of the possibilities with PSL, when used patiently with the proper, related mechanics.
To further drive the point of the need for proper and patient use of available appliances and mechanics, I will be demonstrating in the next blog posts, more brief case reports of borderline Class III cases in younger patients that were treated on a non-extraction basis, but using conventional pre-adjusted fixed appliances and related mechanics.
Your questions, ideas and constructive comments are welcome – as always – in the comments section below.