14 SPECTRUM Implants — Vol. 8 No. 3 — Fall 2017

Six Hacks foryour next FixedFull Arch Case

Dr. Frederick Li - Tips andtricks for treating the fullyedentulous arch

It has been many years since Dr. Paulo Malodescribed his innovative method of treating thefully edentulous arch1 known as All-on-Four®. The

ability to slant implants and the utility of immediateloading through fixed full arch implant restorationshas reduced the time, cost and invasiveness involvedin treating the edentulous arch. Based on the fast-growing body of research and the sheer number ofpatients now successfully treated, this treatmentmodality has gained acceptance with most cliniciansinvolved in implant dentistry. Developments inmethods, materials and components have improvedpredictability, decreased treatment time and reducedcosts for patients. As with any technique – even thosethat have been around a long time - there are newapproaches that help to improve the efficacy andefficiency.

Here are six “Hacks” that I have found to simplifythe process of treating the edentulous arch with thefixed full arch implant restoration technique. For thepurposes of clarity and consistency throughout thediscussion, I have employed the AVINENT™ OCEANImplant system as my example system of choice inillustrating the key points.

Use a moderately aggressivethreaded implant

Stability of the implant has always been a key factorin placing implants in the fully edentulous arch. Inmany full arch cases, implants are often placedimmediately into sockets and have limited bone forinitial stability. Immediate loading also requires highstability of the implant in bone. Dental implantswith aggressive threads and a taper help achievedesired stability in challenging conditions. Yet,implants with too aggressive a thread can be anegative factor. Edentulous arches often have alimited quantity of bone after years of edentulism.Aggressively threaded implants can break throughthe alveolar ridge or perforate into the sinus.Inadvertent transposing from planned osteotomiesat placement is another issue. I have found that usinga tapered implant design with moderately sharpthreads is a good compromise to achieve the righthandling properties for full arch cases.

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Figure 1 – Example of AVINENT™ tapered implant design withmoderately sharp threads.

Figures 2 and 3 - AVINENT™ implants placed into sockets.

Fig. 2

Employ an implant system with avariety of sizes

Full arch cases require precise placement of implantsin limited quantities of bone. The aforementionedrequirement for implant stability also increases thechallenge with these cases. A variety of implant sizesfrom short and wide implants (e.g., 5X7mm to avoidthe nerve and sinus) to longer ones (e.g., 15mm formaximum stability) allow the practitioner to achieveideal positioning for the surgical and restorativerequirements of full arch cases.

Make sure a variety of transmucosalangled abutments are available to you

Since the introduction of the All-on-Four® technique,Paulo Malo has established the success of rate ofusing slanted implants. The degree of angulationmatched with the desired location of the access holein the restoration can vary significantly from caseto case. Having a variety of transmucosal angledabutments (e.g., 17 degree, 24 degree and 30degree) at a variety of heights allows for idealpositioning of the prosthetic connections. Inaddition, an internally hexed system also allows 6different positions. Having fewer heights andpositions can restrict your flexibility dramatically.Yet, having more makes placing abutments difficult

and adds to confusion. The AVINENT™ system hasan adequate range of heights and positions thatallow for maximum flexibility of abutment selectionwithout introducing the confusion of having toomany options.

Choose an implant system with asingle connection

You will find that a variety of transmucosalabutments have to be purchased for each implantconnection size. Despite the best advance planning,most full arch cases require an abundant selectionof abutments before the surgery date. An implantsystem with a single connection size (for eachdiameter of implant) can reduce the cost of highvalue stock by multiples. In addition to lower cost,

Figure 4: Implants placed in slanted positions to maximize anterior-posterior spread and used in regions of limited height of bone.

Fig. 3

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having a single connection reduces confusion for thesurgeon and staff. You will find, as I did, that this is amajor and important factor.

Place additional implants

Though Paulo Malo described his technique as “All-on-Four®, placing more than four implants is anadvantage in most cases. In the upper arch, the boneis softer. Many practitioners prefer to place moreimplants to distribute the bite force. Another factor isthe difficulty in getting stability of implants in idealprosthetic positions. There are common scenarioswhere the ideal positions for the implant does notallow for adequate stability of immediate loading.These implants can be still be placed and loaded afterthe appropriate healing time but in the meantime,additional implants be placed in other locations toachieve loading of a fixed temporary. Obviously, costis a factor in this decision as well. Implant systemsthat are available at a reasonable cost (withoutsacrificing the other important aspects just outlined)allow more implants to be placed, giving flexibility inthe treatment plan.

Use a milled temporary

Immediate loading of full arch cases has been a huge

Figures 5 and 6: Implants are placed at differentangles within anatomical constraints.Transmucosal abutments of different heights and angles allow for idealprosthetic placement of screw holes.

Figure 7: Renderings of AVINENT™’s range ofangulated options: 17 degree; Avinent™’s uniqueand popular 24 degree angulation for full archcases; and 30 degree.

Fig. 5 Fig. 6

Fig. 7

Figure 8: A variety ofAVINENT™ transmuosalabutments, all fitting all4 diameters ofAVINENT™ implants.

Figure 9: Extra implants placed

for better case predictability.

Avinent™ ad

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Figures 10 and 11: A fixed acrylic temporary converted chairside from a complete denture. Note the differences in materials.

Fig. 10 Fig. 11

Figure 13: Mesh of design of new temporary and older chair sidetemporary.

Figures 15 and 16: Lab milled one piece temporary.

Figure 14: Design of new temporary.

Fig. 15 Fig. 16

Figure 12: Scan of chairside immediate temporary bridge.

TriHawk full page

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advantage. It provides relatively even forcedistribution over the implants versus a denture thatis still very mobile despite relines. Patientacceptance is superior as the final result is muchcloser to natural dentition than any removableprosthesis. The largest advantage is the temporaryacts as a trial run of tooth position, verticaldimension, and esthetic considerations prior tofabricating the final prosthesis.

Yet, one of the major headaches associated withimmediately loading is the weakness of theconverted acrylic prosthesis. Breakage is commonand requires “emergency” clinic time to fix, alongwith causing patient dissatisfaction. The reason forthe lack of strength of an acrylic fixed bridgeconverted from a complete denture can usually betraced to the number of different materials used inits fabrication. For example, common materialchoices will be the pink denture acrylic, the acrylicteeth, the composite or material used to pick upthe temporary abutments and the actual temporaryabutment themselves. These different materials donot necessarily bond with each other and flex atdifferent rates. Strength can be improved with the

use of lab acrylic and the help of a lab technician ordenturist, but contour and material porosity is farfrom ideal.

A milled, lab-processed temporary solves all ofthese challenges. It is a one piece design createdfrom a single material, providing superior strength,contour and polish to reduce breakage and plaqueaccumulation. Though a full arch milled temporarycan be used on the day of surgery, it may be betterto start the case with a conventional conversionfrom an acrylic denture and to fabricate the milledtemporary after the patient is comfortable with thetooth positioning, vertical dimension of occlusionand esthetics of the initial conventional conversion.Fabricating a milled temporary is relatively easywith the lab being able to scan the chair sidetemporary and designing the new one as areplication.

Conclusion

Treating the fully edentulous arch is full ofchallenges, ranging from phonetics, verticaldimension of occlusion, esthetics, and function to

Figures 19 and 20 - Restoration of an upper full arch with acrylic fixed hybrid bridge.

Fig. 19 Fig. 20

Fig. 17 Fig. 18

Figures 17 and 18 - Restoration of an upper full arch with ZR bridge on implants.

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The author

Dr. Frederick Li graduated fromthe University Of ManitobaCollege Of Dentistry. Desiring tofurther his dental education andexperience, he moved to NewYork City and completed twoyears of dental residency inhospital facilities associated withCornell Medical Center andColumbia University. DentalImplantology was a focal

component of the post-graduate training, enabling Dr. Li togain surgical implant experience from some of the top implantsurgeons and prosthodontists in the Greater New York Region.

Dr. Li is a graduate of the Misch Implant Institute, a Fellowof the International Congress of Oral Implantologists andAssociate Fellow of the American Academy of ImplantDentistry. A general practitioner in private practice in Vancouverwith a large volume of surgical and prosthetic dental implants,Dr. Li lectures across Canada. He conducts a variety of trainingprograms on Oral Implantology and dental implant placementwhile also mentoring a large implant study club in theVancouver area.

oral hygiene. Any progress in technique andmaterials are welcome in making this proceduremore predictable, efficient and cost-effective forour edentulous patients.

As illustrated in the two final restorative resultspresented in Figures 17 – 20, the biggest benefit offull arch fixed implant restorations is the beautiful,natural esthetics available to the patient, functionas close as possible to natural dentition – and thegratification available to the clinician in being ableto provide them reliably and affordably. n

Bibliography:1. Clin Implant Dent Relat Res. 2003;5 Suppl 1:2-9. “All-on-

Four®” immediate-function concept with Brånemark Systemimplants for completely edentulous mandibles: a retrospectiveclinical study. Maló P, Rangert B, Nobre M.

2. Clin Implant Dent Relat Res. 2015 Oct;17 Suppl 2:e531-41. doi:10.1111/cid.12282. Epub 2014 Dec 23. All-on-4® TreatmentConcept for the Rehabilitation of the Completely EdentulousMandible: A 7-Year Clinical and 5-Year RadiographicRetrospective Case Series with Risk Assessment for ImplantFailure and Marginal Bone Level. Maló P, de Araújo Nobre M,Lopes A, Ferro A, Gravito I.