Bar-retained overdenture mounted on 4 implants
Our female patient L.P.V., 73, presented to our clinic with the following requests:
- She desired to have her old bridges replaced as her teeth underneath had decayed beyond repair.
- She knew some of her teeth required to be extracted but was not in favour of a full denture. She desired a more firmly secured solution without a palate.
- She wished to have her edentulism restored with implants but was against a major bone graft surgery.
- She wanted to recover her smile and her old smiling self, which she had lost due to the old non-aesthetic replacement.
- Restoration of masticatory function.
First panoramic radiograph (February 2017) capturing the initial condition.
First treatment – 3 workdays, extraction of teeth, rehabilitation of the complete oral cavity and the fabrication of provisional removable dentures
Unfortunately neither the teeth nor the old implants could be salvaged, they were all removed due to the infections and inflammations (dental foci) having formed around them. This was done as early as at the first treatment. Once her teeth were extracted and the implants were removed (explant surgery) the patient was immediately given a provisional denture in order not to compromise her self-esteem and enable her to smile over the 4 month-healing period.
The upper root canals prior to the extractions
Panoramic radiograph following removal of the infected and inflamed teeth.
Second treatment, 3 workdays, following 4 months’ healing, the installation of implants
Following 4 months’ healing a CBCT (Cone beam computed tomography) scan was recorded in order to examine residual bone mass in 3 dimensions prior to the implant surgery. As appears from the CT scan, bone height was inadequate in all molar positions, warranting a so-called sinus lift for an appropriate stability of implants. Since the patient was against bone graft, only 4 implants were mounted in both the mandible and the maxilla. Since the primary stability of the implants was excellent, Dr. Suba decided to seal the exposed gums directly with gingiva formers (healing abutments). With implants having primary stability less than 30 Ncm, the exposed gums are fully sealed, yet in such an instance another surgery is required to locate the implants individually and install the protruding gingiva formers with which to shape the gums into the appropriate contour. It is important that the permanent abutment should have an ideal gum contour.
Healing time is determined on the examination of implant stability by the surgeon installing the implants during surgery. Such healing time averages between 3 to 6 months.
The provisional denture fabricated following tooth extraction is relined as per the new, altered anatomical relationships to provide for easy and comfortable wear.
It is important to minimise the wearing time of the provisional overdenture following bone graft and/or the installation of the implant. Patients are advised to only wear their provisional dentures at work or at places where they are required to talk or smile. When at home, please immediately remove the denture. Also make sure you keep your denture and mouth clean and that no pressure is exerted on the denture/implanted area and that the denture does not “wiggle” on the implants. Pressure exerted by the denture restricts blood circulation, hinders healing and may cause cracking or infection, or worst of all, the rejection of the implant, however successful the implant surgery may have been. This is crucial from the point of view of healing.
CT scan showing the mandible. Bone height and width can be examined in 3 dimensions whereby the location and size of the prospective implant can be assigned accurately.
Panoramic radiograph following the installation of the implants with the gingiva formers in place
Third treatment, 10 workdays, after 4 months
Following the 3 month-long mandatory healing period the permanent replacement is ready to be fabricated. In case of our patient L. P. V. upper and lower bar-retained dentures were made as 4 implants can only ensure appropriate stability for a removable denture (overdenture).
This is the most laborious of all treatments. Precision impressions are taken of the implants by means of special, open tray impression copings. Following impression taking several trial insertions or test fittings have to be performed while the dental technician is proceeding with preparation of bars and dentures.
During the framework test fitting the precision of the impressions and the trueness of the bars are verified as all tooth replacements must seamlessly fit the master cast.
At the tooth test fitting the bite and the length of the teeth, the central position of the 2 central incisors and the appropriate rearward curve of the denture are verified (aesthetics). The different test fittings follow one another at intervals varying from several hours to several days, with the dental technicians working at full tilt in the meantime.
L. P. V. was very satisfied with the result. She left the clinic with two very well fitting dentures. She recovered her self-esteem and is able to smile broadly again.
Implant-borne tooth replacements require as much, if not more care and follow-up as natural tooth-borne varieties. There is a very close relationship between oral hygiene, the quantity and quality of tartar build-up and the long-term success of implants.
Overdentures require a reline every 2 to 3 years. Since there are no root canals, the mandible and maxilla are in a continuous, slow progress of decay. Sadly, this is a physiological process that cannot be helped. The bone gradually resorbs which is adversely affected by denture pressure. Seeing as an inaccurate, wiggling denture accelerates bone resorption, annual follow-up check-ups all-important for the dentist to perform a bite check, assess the extent of wiggling, if any, and determine whether a denture reline is necessary. Should the patient fail to show up for the follow-up examinations and if a bite correction and reline are never performed, the wiggling of out-of-true dentures can greatly compromise the implants. Traumatic occlusion, tartar and the inaccurate denture may bring about periimplantitis, which is a highly unfavourable condition causing the bone to resorb uncovering the thread of the implant. The rough implant surface “jutting out” is excellent breeding ground for tartar build-up and bacteria to propagate, causing increased bone resorption and infections till at length the implant is expelled.
Removable bar-retained overdenture borne by implants, on a gypsum cast
The metal base of the bar-retained overdenture and the Straumann Dolder bar joints.
Bar retained upper overdenture without a palate.
Implant-borne bar on a gypsum cast.
Bar secured on upper implants in the mouth
The finished prosthetic work in the mouth