The Effect of a Removable Complete Denture Over One Implant in the Lower Jaw on Hearing Ability

The effect of a removable complete denture and the insertion of one implant in the lower jaw and the loading of this implant on the hearing ability of patients will be studied, so the hearing ability will be measured by using the PTA test for 30 patients in the age of 50-65 years old. The hearing ability measurement will be done in 4 different periods of time. Before and after using the denture, before and after the implant insertion, and after loading the implant with the same complete denture. The implant surgery will be done in two phases: the first is to insert the implant in the bone and cover it by suturing until it integrates with the bone after 3 months, the second is to start the process of loading the implant with the denture.

Tanaka et al mentioned in their study that in accordance to the WHO, about one third of the people older than 65 years old is somehow affected by hearing loss. Although hearing loss is not a life-threatening condition but it is related to medical and psychological problems such as depression and social isolation. Reduction in the occlusal vertical dimension is considered one of the factors that cause a decline in hearing ability. A study of Shreedhar et al found that there is improvement in hearing ability between loading two implants in the canine regions in the mandible with a removable complete overdenture and after one month of the loading. In their study, the hearing threshold improved from 40 to 25 decibel and the improvement is associated with transmission of vibrations from the oral cavity through the bone. Implants in the mandible has been associated with improvement in hearing although the mandible is not in direct contact with the skull, and Ozer et al study found that the hearing acuity through the bone was not different between the upper and lower jaw. In Tanaka et al study teeth loss was associated with the increased prevalence of hearing loss. King et al found important improvement in previously existed hearing loss after the replacement of missing teeth with a removable complete overdenture. Furthermore, Schell et al study found that hearing acuity was worse in the edentulous patients group than the other groups, which suggests a relation between hearing loss and the dentate status. A similar study of Peeters et al mentioned that the discrepancy between patients who had complete dentures and patients who had loss in the occlusal vertical dimension strengthen the hypothesis that there is an association between hearing loss and the occlusal vertical dimension. As for the single implant retained complete overdenture, there has been several studies, which are mentioned in carl's Misch book that found this treatment to be valid, especially for patients who suffer from removable dentures and have problems in mastication.

The available evidence on the relationship between dentate status and hearing loss is limited, so understanding this relationship could help prevent or delay the occurrence of hearing loss. The possibility of suggesting implant placement and loading the implant with a removable complete overdenture as a way to improve bone-conducted hearing in edentulous patients will be studied.

In this study, we are going to measure the hearing ability of edentulous patients 4 times: First, before using the complete denture. Second, after using it for one month and before placing the implant. Third, 10 days after placing the implant in the midline of the mandibular jaw. Fourth, after 1 month of loading the implant with the removable complete overdenture. The null hypothesis is that there is no statistically important difference in hearing thresholds by bone conduction between the studied periods of time. This study will be done on 30 patients and a written consent will be taken. The hearing ability test will be done in Al-Mowasat hospital after the examination of the patient by an otolaryngologist before the first hearing test. The hearing ability test is called Pure Tone Audiometry or PTA.

Eligibility Criteria:
Inclusion Criteria:

* Age between 50-65 years old.
* No previous experience in removable complete dentures.
* Enough bone in the midline of the mandibular jaw that permits the placement of a single implant no less than 10 mm in length and 3.4 mm in width.
* Hearing threshold of the patient between 40-70 decibel.
* The ability of the patient to fill out the questionnaire and commit to follow up sessions.

Exclusion Criteria:

Having one of the variables that are connected with hearing loss, which are:

* usage of hearing aids.
* Uncontrolled diabetes.
* Uncontrolled hypertension.
* Balance problems.

In addition to risk factors that are associated with hearing loss, which are:

* stroke
* kidney disease

In addition to contraindications for implant surgery, which are:

1. definitive contraindications: Recent myocardial infarction, valve replacements, cardiovascular diseases ,and presence of immunodeficiency, bleeding problems, drug abuse, and psychological disease.
2. Relative contraindications:

Osteoporosis, heavy smoking, uncontrolled diabetes, hypothyroidism.