[Effects of wearing dentures on sleep breathing among edentulous people: a preliminary study].

OBJECTIVE: To investigate the effects of wearing dentures on sleep breathing among edentulous people. METHODS: Nine edentulous people were recruited to participate in this selfcontrolled case series clinical study. Polysomnogram (PSG) was carried out on two consecutive nights, on one night the patients slept wearing dentures, and on the other without dentures. The indexes such as apnea and hypopnea index (AHI), L-SpO2, and morning blood pressure etc. were compared. RESULTS: Among the nine edentulous people, eight showed a higher AHI when they slept with dentures, and only one showed a lower AHI. The average AHI of the nine edentulous people was 8.82 without dentures and 11.72 with dentures, which meant that AHI was significantly higher when the edentulous people slept with dentures in their mouths (P<0.05). While no significant differences were found in the score of L-SpO2 and morning blood pressures (P>0.05). CONCLUSION: Wearing dentures might lead to an increase of AHI during sleep among edentulous people.

[Effect of early-loaded small diameter implants retained mandibular overdentures on masticatory performance].

OBJECTIVE: To evaluate the clinical effect and masticatory efficiency of two early loaded Small Diameter Implants (SDI) retained mandibular overdentures. METHODS: Eight mandibular edentulous patients received two SDIs insertion between mental foramina. The mandibular overdentures were connected with implants for early loading in the period of 2-4 weeks following implant insertion. The data of visual analogue scale (VAS) of denture satisfaction and masticatory ability were collected at baseline, two weeks, three months and six months following overdenture loading. Masticatory efficiency was evaluated before surgery and six months after overdenture loading. RESULTS: Within the period of six months following overdenture loading, all the 16 implants remained stable. Compared with the baseline, the VAS data of denture satisfaction,stability, masticatory and poltophagy ability two weeks, three months and six months after overdenture loading were significantly improved with 30 degree (P<0.01), especially the masticatory and poltophagy ability of hard and crisp food. The value of masticatory efficiency improved considerably six months after overdenture loading (P<0.01). CONCLUSION: Mandibular overdentures retained by two SDIs can significantly improve patients' denture satisfaction and masticatory efficiency, and provide more rational diet.

Time Efficiency of Immediate Loading of Full-arch Implant Reconstructions Using Prefabricated Prostheses Located by an Anchor Pin: a Pilot Study.

OBJECTIVE: To investigate the time efficiency of prefabricated prostheses located by an anchor pin stereolithographic attachment system for immediate loading implant reconstruction of completely edentulous jaws and compare it with the conventional protocol. METHODS: Edentulous patients were recruited and randomly assigned into two groups: the full digital workflow group (digital group) and the conventional workflow group (conventional group). In the digital group, a provisional prosthesis was fabricated before surgery using a fully digital workflow and delivered immediately after implant placement. The positioning of the provisional prosthesis was guided precisely by the anchor pin attachment system. In the conventional group, the provisional prosthesis was fabricated after implant placement using a conventional procedure. Clinical and laboratory time efficiency were recorded, and clinician and patient satisfaction were evaluated. RESULTS: Six patients were enrolled in this pilot study and 57 implants were placed following the guided surgery protocol. Of these, 54 were immediately loaded. The total clinical chair time in the digital workflow group was significantly less than that in the conventional workflow group (digital 60.0 ± 13.2 minutes; conventional 106.7 ± 24.7 minutes) (P = 0.045). The total post-surgery procedure took significantly less time in the digital group than the conventional group (digital 202.5 ± 22.5 minutes; conventional 403.7 ± 55.4 minutes) (P = 0.004). The patients' and clinicians' satisfaction with the provisional prostheses was similar in both groups. CONCLUSION: Time efficiency in immediate loading of implant-supported full-arch fixed restorations was improved with prefabricated prostheses located by the anchor-pin-attachment system. Less postoperative chair time was required in the digital group than in the conventional group.

Accuracy of Intraoral Scanning of Edentulous Jaws with and without Resin Markers.

Objective: To evaluate the accuracy of digital models obtained from intraoral scanning of edentulous maxilla and mandible models with and without resin markers. Methods: A pair of standard edentulous models were scanned using a laboratory scanner and saved as reference models. The edentulous models were fixed onto a phantom head and scanned with an intraoral scanner (IOS) five times each. Six resin markers were attached on the maxilla model and two on the mandible model, and another five intraoral scans were taken of each model. The scanning time and number of images were recorded. The digital models obtained using the IOS were superimposed on the reference models using image processing software. The trueness and precision of the models made using the IOS were evaluated, and the scanning time and number of images were also compared. Results: The average trueness and precision of the IOS in the maxilla model with resin markers were 135.50 ± 36.28 µm and 254.55 ± 40.62 µm, respectively, while those in the mandible were 161.40 ± 55.45 µm and 368.75 ± 91.03 µm, respectively. Placing resin markers on the edentulous maxilla and mandible did not improve the trueness of the IOS, but placing resin markers on the edentulous maxilla improved the precision and scanning efficiency. However, placing resin markers on the buccal shelf of the edentulous mandible decreased the precision and increased the scanning time. Conclusion: Resin markers placed on the hard palate of edentulous maxillae could improve the precision of the IOS and improve scanning efficiency. However, they did not affect the trueness of the IOS for edentulous maxillae or mandibles.

[Evaluation of clinical application of ACP classification for edentulous patients].

OBJECTIVE: To evaluate clinical application of American College of Prosthodontics classification system for complete edentulism; and to analyze the relationship between clinician's rating of general degree of difficulty of each case and patients' rating of denture satisfaction. METHODS: One hundred and seven edentulous patients were examined clinically using American College of Prosthodontics (ACP) classification for complete edentulism. The least heights of patients' mandible were measured on panoramic radiographs. Clinician rated general degree of difficulty of each case on visual analogue scale. Six month following denture delivery, patients rated their denture using Mcgill satisfaction Visual Analog Scale (VAS). Multivariate linear regression analysis were conducted to analyze the relationship between clinician's rating of general degree of difficulty and mandibular bone height adjusting for confounding factors such as mandibular ridge form, soft tissue quality etc. Pearson correlation analysis was conducted to analyze the correlation between clinician's rating of case difficulty and patients' rating of denture satisfaction. RESULTS: Advanced residual ridge resorption were found in around 80% (83/105) of all the cases. When the least mandibular bone height were measured on panoramic radiographs, intra-examiner reliability was 0.96, inter-examiner reliability was 0.90. Cases were rated as more difficult when patients showed lower mandibular bone height, unfavorate ridge form (knife ridge and irregular ridge), mobile soft tissue and longer period of wearing time of their previous dentures. No significant correlation (r<0.1) was found between clinician's rating of degree of difficulty of each case and patients' rating of denture satisfaction 6 month following delivery of prostheses. Clinician rated cases in which patient's mandibular bone height was lower than 11 mm as 8.8%-16.1% more difficult than those in which patient's mandibular bone height was higher than 11 mm (P<0.05). CONCLUSION: ACP classification for complete edentulism showed good intra- and inter-examiner reliability, and is an useful tool for clinical evaluation of edentulous patients' oral condition. However, there was no significant correlation between clinicians' rating of difficulty of cases and patients' rating of denture satisfaction.

Clinical Efficiency and Patient Preference of Immediate Digital Impression after Implant Placement for Single Implant-Supported Crown.

OBJECTIVE: To evaluate the time efficiency and patient preference of three impression techniques by comparing immediate digital impression performed directly after implantation with regular digital impression and conventional implant impression performed 3 months after implantation. METHODS: Twenty consecutive patients with a missing single molar or premolar who received implant treatment were recruited into this prospective self-controlled clinical trial. Three different impression techniques were performed after implant surgery on all the participants: An intraoral scanning (IOS) impression performed immediately after implant placement (immediate digital impression) was compared with a regular digital impression and a classic polyether impression (conventional implant impression) performed 3 months after implant surgery. The operating time of each impression technique was recorded. Patients were asked to complete a visual analogue scale (VAS) questionnaire on their perception of the three techniques to describe their satisfaction and preference. Statistical analyses were performed with the Wilcoxon signed rank test. RESULTS: The clinical time of the immediate digital impression (10.97 ± 2.1 min) was significantly shorter than that of the conventional implant impression (14.45 ± 3.0 min) (P < 0.05). The mean time of the immediate digital impression (10.97 ± 2.1 min) was statistically the same as that of the regular digital impression (10.23 ± 2.7 min) (P > 0.05). Participants' subjective evaluation indicated higher satisfaction with the immediate digital impression than with the regular digital impression and the conventional implant impression. CONCLUSION: The immediate digital impression was more efficient than the conventional implant impression and had the same efficiency as the regular digital impression. Among the three impression techniques, the participants showed higher satisfaction with the immediate digital impression.