Dr Robert Hayes presents this Neodent Grand Morse clinical report.
While strongly supporting the belief that the bone loss we unfortunately observe around some teeth and implants is caused by inflammatory change, and that biomechanical factors are frequently a major contributing cause of inflammation via unprotected parafunctional overloading, it is clear that the host response to bacterial plaque can also be sufficient cause of terminal bone loss without any significant mechanical cause of inflammation.
Debbie has been thirty years in our periodontal programme, commenicing with three-monthly hygiene visits when in her early 30s and has spent the last 15 years under the care of the periodontist. Her plaque control has varied over this period but most of the time has been very good.
As is common with periodontal cases we believe that smoking has been a significant contributor to the poor host response to the generally minimal plaque observed at frequent visits. She gave up smoking in her late 40s when there was already considerable recession generalised across the maxillary teeth.
In her 50s, the upper central incisors became extremely mobile and were replaced by an adhesive bridge which has never been in occlusion or required re-bonding as Debbie has a malformation of the mandibular articulation which has given her a lifelong anterior open bite with only the second molars in contact.
Although there is a mild Class III tendency and the suggestion of a large tongue, there is no tongue thrust habit or tightness of the oral musculature. Debbie has been closely informed of her dental progression and respnded over a period of time to smoking cessation advice and oral hygiene instruction.
In winter 2017/18 we reached the conclusion that because of her absolute rejection of any removable option or acceptance of spaces or a reduced arch we would opt for NeoArch™ utilising Grand Morse™ (GM) Helix Aqua as the implant body of choice. This would give great advantageof the bacteria tight Grand Morse™ connection, thus providing the established reduction in risk of ongoing bone loss from plaque accumulation, microgap formation, micromotion and high marginal cortical bone loading seen with many parallel sided internal and external hex abutment connections.
The surgery was performed in March 2018 unter ITI sterile protocol with articaine 4% local anaesthetic. Following administration of 600mg ibuprofen, 3G amoxicillin and 10ml anaesthetic, the mobile upper dentition was extracted uneventfully and the gloves changed for open surgery.
A single crestal incision was made from the palatal gingival margin of the right molar to the palatal gingival margin of the left molar and the buccal flap fully reflected with all gingival interdental tags attached, leaving a smooth palatal aspect to the soft tissue which was gently released for reflection during ridge preparation to a flat bone shelf using a 6mm diameter cross cut bone bur.
The planned prosthesis was briefly placed to confirm seating, occlusion and aesthetics and then exchanged for a clear surgical stent for pre-placement observation. The chosen implant positions and angles were transferred from the CBCT scan and marked into the ridge using the excellent Neodent point drill which includes extremely clear laser markings.
The osteotomies were sequentially advanced by eye at the predetermined angles to a diameter of 3.75mm and depth of 18mm at the posterior sites and 15mm at the anterior sites. Followed by motor insertion at 50Ncm and 50rpm of two 4×16 Helix Aqua implants posteriorly and 13mm anteriorly to full depth, ceasing rotation when the internal hex flats were facing the most prosthetically advantageous aspect with the head of the implant 2mm below the bone shelf.
Slight trimming was undertaken with the 6mm bur to the distal aspect of all four osteotomies to provide a depression to house 30º multiunit abutments on the posterior implants and two 17º multiunit abutments on the anterior implants which were readily placed to 20Ncm utilising the excellent ProTaper Gold NiTi coated star driver, which like the implant placement device, locates positively and efficiently to provide an extremely safe pick-up of components.
The soft tissues were sutured and the surgery completed in 55 minutes. The first titanium temporary multiunit coping was attached to the upper right anterior implant and the transparent surgical guide positioned and carefully observed to determine the emergence position and angulation to inform the penetration of the initial prosthesis with a 3mm diameter round steel bur.
The aperture is checked and rechecked intraorally with sequential adjustments using the bur until it will seat in the correct occlusal and aesthetic position without metal contact. The procedure was repeated for the left anterior, right posterior and eventually left posterior coping until the prosthesis returned to the original tissue born position without interference from contact with titanium components. As usually the access positions were palatal to the lateral incisor tips and within the occlusal prosthetic envelope of the first molars. No second molars are provided in order to minimise cantilever and reduce occlusal loading.
Once the prosthesis has been checked using a putty occlusal matrix produced on the articulator during the laboratory process and any interference eliminated by extra-oral trimming of the titanium copings they were filled with compressed PTFE tape and isolated with rubber dam.
The prosthesis is washed, dried and coated with bonding agent, relined with UFL Gel Hard and replaced intraorally under firm occlusal pressure by the patient closing with the occlusal guide in place.
A large round diamond bur is used in a fast handpiece with high volume aspiration to uncover the copings sufficiently to remove the PTFE tape and achieve unimpeded seating of the prosthetic screw driver mounted in an Anthogyr Torq Control which is used to counter-rotate the prosthetic screws and remove the prosthesis for conversion into an implant supported bridge using standard laboratory techniques of relining, trimming and polishing. The relining is arranged to an ovate pontic design to compress the gingivae and form a smooth, level, gingival trough.
In our clinic, after 15 years’ experience with 700 arches, we acheive this freehand but when starting out one can alternatively take an open tray impression with putty only (to avoid fluid materials entering the open tissues) and then work from a plaster or silicon model.
The finished prosthesis is attached using the four prosthetic screws with the Anthogyr set at 10Ncm to produced a controlled gingival compression. The access points are filled to 1.5mm below the oral surface with well compressed PTFE tape using the small tip of a standard amalgam plugged and capped off with light cured Clip or self-curing Fuji IX, which seem to seal more effectively than composite resin – certainly there is less odour on removal. Occlusal adjustment is undertaken, using fine blue paper and, in this case, the pre-existing posterior loading of anterior open bite was reversed by trimming the acrylic molars out of contact and undertaking sequential adjustments to the resin cusps until a balanced Class I occlusion was achieved.
After final polishing, the patient was seated for rinsing and handed a mirror to assess the result. Debbie’s reaction: “Oh my god – they’re beautiful – and my front teeth come together – I’ve never had that!”
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Dr Robert Hayes MSc Imp Dent, Dip imp Dent RCS, MF GDP, BDS is an accredited inplant training practitioner and mentor in implant dentistry.