This patient was referred to my practice for a new lower complete denture after extractions of her remaining lower teeth a few months ago.
She is 75 years old, with no significant medical history. Her only problem is that she can’t wear a lower denture with a very thinned ridge. Her referring dentist anticipated that . Her potential denture would most likely have poor retention and instability . She too is exposed to difficulty in coping which could resulted in pain, denture sores and problems with function such as eating and talking.
Examination , extra-oral, intraoral and radiography.
She came with a satisfactory upper partial denture and fully edentulous lower ridge without any denture. Upon examination and coupled with radiography and CBCT, patient appears to have a very thin and knife-edge anterior lower ridge.
A construction of a new lower denture and keeping her upper partial denture, so that we are not changing too many factors in her mouth. By placing just one implant as suggested by authors in (1) , it is placed in front and centre of the lower jaw, so that the patient could conveniently clip on a mandibular overdenture and hopefully enjoy stability and comfort. In this case we opted for this solution coupled with alveolectomy to remove the knife-edge ridge.
Fabricate the lower denture as usual with space to house the ball-attachment
- Lower denture is more challenging than upper dentures because there is no suction to hold them in. This lack of suction, along with jaw and tongue movement during chewing and speaking can cause a lower denture to be very uncomfortable and sometimes painful. The lower denture simply floats on the ridge where the teeth used to be and does not stay in by using suction like the upper. Because lower dentures slip and slide, and as a result cause continuous gum pain when eating, the snap on denture option is a must for lower dentures. For many patients, it is the minimum standard of care for a satisfactory quality of life.
- With people now living longer, the number of denture wearers is steadily increasing. Many people in this demographic are no longer financial and can be quite disadvantaged. Finding a solution to improve their quality of life in a cost-effective manner has been critical.
- This treatment, involving just single stage surgery, followed by the fitting of a mandibular overdenture may be an ideal solution for some patients suffering the discomfort of ill-fitting lower dentures.
- Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used.
We use this protocol of an immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading.(2) This study showed a long term success of 100%.
However, Kronström et al. (3) reported a failure rate of 17.6% after 12 months when immediate loading of a single median mandibular implant was applied . So results of immediate loading of a single median mandibular implant retaining an overdenture are conflicting.
In order for this kind of prosthesis to function effectively and to also be aesthetic, careful attention must be given to diagnosis and treatment planning. The definitive prosthesis must be placed within the confines of the neutral zone/neutral space with particular attention to the implant position limitations, restorative space, the aesthetic space, and the condition of the opposing arches. The optimal prosthesis becomes the best guide for implant placement. A badly designed prosthesis cannot be replaced by any kind of attachments.
#Alveolectomy, #alveoloplasty, #denture -retention, #pre-prosthetic #surgery, #undercuts
(1) Glen Liddelow, Patrick Henry, http://research-repository.uwa.edu.au/files/3214473/Liddelow_Glen_J_2008.pdf
(2)Nicole Passia, Miha Brezavšček, Matthias Kern http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4040476/
(3)Kronstrom M, Davis B, Loney R, Gerrow J, Hollender L. A prospective randomized study on the immediate loading of mandibular overdentures supported by one or two implants: a 12-month follow-up report. Int J Oral Maxillofac Implants. 2010;25:181–18 http://www.ncbi.nlm.nih.gov/pubmed/20209200