The influence of the degree of maxillary defect closure and palatal shape of maxillary prosthses on the ability to speech

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Purpose : The goals of treatment to patient having maxillary resection is to overcome deterioration of the oral major functions and disorders in the speech function, the masticatory function and the swallowing function due to their maxillary defect.To achieve these goals from a prosthetic point of view, sufficiently thorough seal of maxillary defect area should be accomplished with a maxillary prosthesis. In order to evaluate the treatment effects of the denture, quantitative evaluation is required of the degree of maxillary defect closure and of the improved speech capabilities after the denture is in place. This study examined the method to evaluate the degree of recovery of speech function for installing a maxillary prosthesis in clinic treatment room.Measurements : Using both omni-directional and uni-directional microphones and an MDrecorder (Mini Disc recorder), I conducted the following experiment :1) I made digital recordings of a short sentence in Japanese "Sakura no hana ga sa … More kimashita (The cherry blossoms were in full bloom)" read by an adult in an anechoic chamber using both types of microphones. The reader had a full set of his natural teeth and did not have any abnormalities in his pronunciation (hereafter refereed to as the "normal person").2) I also made digital recordings of the same sentence read by normal persons and patients installing a maxillary prosthesis in clinical room.3) I made further recordings of the same sentence spoken by the patient after changing the palatal shape of denture plate.4) I then analyzed the clarity of speech in the various recordings by having five adults who did not have any hearing impairment listen to the recordings. In addition to, the recordings were analyzed on a personal computer.Results and Discussion1) Normal person(1) In the anechoic chamber : No difference was seen in the waveforms of the omni-directional and unidirectional recordings.(2) In the clinic treatment room : Various extraneous noises were heard in the treatment room recordings using both types of microphones. However, after comparing the two readings, the uni-directional microphone was judged to pick up less noise, so I decided that it was more suitable for recording voices in the treatment room.2) Patient installing a maxillary prosthesis(1) The speech clarity in the recordings was fine. This may be because a good seal was made between the oral and nose cavities by the denture.3) The palatal shape of the denture plate seemed to seal the oral cavity well on both sides, which accounts for the clarity of speech. When I produced a denture which could change the palatal shape of the denture the patient died. Therefore I had to quit this experiment prematurely. Less