Diagnostic Testing Using Pterygomaxillary Notches and Retromolar Pads on Casts to Check Horizontal Jaw Relation.

OBJECTIVE: To verify horizontal jaw relations using anatomical marks on a cast and evaluate the efficiency and accuracy of the test on checking the horizontal relation. METHODS: A total of 200 patients with a loss of posterior occlusion were recruited. After casts were made and the horizontal jaw relation was recorded, the pterygomaxillary notch and retromolar pad were identified bilaterally on the maxillary and mandibular casts. On each cast, a vertical line was drawn to bisect the anatomical landmarks and the distance between the two vertical lines was measured. Using the result of the wax try-in appointment and the corresponding measurements, a diagnostic test was conducted. A receiver operating curve was created and the maximum horizontal distance between bisecting points that still obtained correct jaw relations was determined to be a criterion. The accuracy of the test to verify horizontal jaw relations was evaluated. RESULTS: The area under the curve of the receiver operating curve was 0.833 (P < 0.05). With a maximum Youden index, the d value threshold was 1.0 mm. Using 1.0 mm as a criterion to check the horizontal relation, the sensitivity of the test was 0.76 and the specificity was 0.93. The kappa value for different researchers was calculated to be 0.79 (P < 0.05). The intraexaminer 1 reliability gave a kappa value of 0.76 (P < 0.05), and intraexaminer 2 gave a value of 0.81 (P < 0.05). CONCLUSION: The test for verifying the accuracy of horizontal jaw relations is reliable. If horizontal distance is measured as greater than 1.0 mm at the jaw relation record appointment, the recorded horizontal jaw relationship may be wrong and need to be reexamined.

A review about the application of phonetic methods in deciding the jaws relation of complete denture.

Speech could be used, because it was a neuromuscular movement without teeth contact. The method was stable, however it was used more in vertical relation deciding. More study was needed in the horizontal relation deciding. This article was to explain why and how to use phonetic method to decide jaws relation, through literature review.

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.

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.

[The modified lip-tooth-ridge classification: a guide for edentulous maxillary arches].

According to the width and height of the maxillary alveolar ridge, the maxillary edentulous jaws can be divided into three categories by using modified lip-tooth-ridge (MLTR) classification. Class Ⅰ is characterized by sufficient bone available for implants in the vertical and horizontal aspects and is suitable for fixed implant-supported prostheses. Class Ⅱ is characterized by sufficient bone amount available for implants in a horizontal aspect but insufficient for lip support and is suitable for a fixed detachable implant-supported prosthesis. Class Ⅲ is characterized by inadequate amount of bone for implants (with vertical or horizontal components) and is suitable for the use of zygomatic implants or traditional complete denture. Patients belonging to Class Ⅰ can be further classified into two sub-categories according to the height of the alveolar ridge. The first subclass is characterized by minimal bone deficiency and is suitable for a conventional implant-supported "crown and bridge" prosthesis. The second subclass is characterized by a larger vertical deficiency than that of the first subclass and is suitable for implant-supported hybrid prosthesis. The MLTR classification system can help the dentist to determine whether the patient is suitable for implanting dentures and whether fixed denture or removable denture is appropriate for the patient, select indications, reduce complications, and achieve long-term results.

[Pilot evaluation of masticatory efficiency and patients' satisfaction in long-centric occlusal pattern complete denture wearers].

OBJECTIVE: To assess the masticatory efficiency and patient' satisfaction in long-centric occlusal pattern complete denture wearers. METHODS: The anatomic occlusal pattern and long-centric occlusal pattern complete dentures were made for each of 10 edentulous patients with severe alveolar rigde absorption simultaneously using the technique of interchangeable artificial teeth. The order of delivery of different occlusal pattern complete denture was determined according to randomized principle. For each kind of occlusal pattern complete denture, the masticatory efficiency was measured with spectrophotometer after the dentures were worn 2, 4, 6, 8, 10 and 12 weeks. A psychometric questionnaire was completed by the patients after wearing the dentures for more than three months and analyzing the patients' rating of the denture satisfaction. RESULTS: No significant differences in masticatory efficiency was found between the long-centric occlusal pattern complete denture wearers and the anatomic occlusal complete denture wearers. The patients' grade of denture satisfaction in long-centric occlusal pattern complete dentures wearers was significantly better than that in anatomic occlusal denture wearers (P<0.05). CONCLUSION: Complete denture with long-centric occlusion can be used to improve the clinical effect of edentulous patients with severe absorption of residual alveolar rigde.

[Relationship of the terminal position of the muscular contraction path and centric relation position in different vertical dimension].

OBJECTIVE: To investigate the relationship of the terminal position of the muscular contraction path and centric relation position with different vertical dimension. METHODS: The terminal position of the muscular contraction path and centric relation position with different vertical dimension were recorded for ten edentulous patients with gothic arch. RESULTS: The mesial distance between the terminal position of the muscular contraction path and centric relation position increased with the vertical dimension. The lateral dimension between the terminal position of the muscular contraction path and centric relation position, the distribution of the terminal position of the muscular contraction path are not correlated to the vertical dimension. The center of the terminal position of the muscular contraction path is 1-4 mm ahead of the centric relation position and (0.42 + or - 0.47) mm lateral to the centric relation position. The distribution of the terminal position of the muscular contraction path is (1.36 + or - 0.58) mm in the mesial-distal direction, (1.56 + or - 0.62) mm in the lateral direction. CONCLUSION: With the increase of the vertical dimension, the mesial distance between the terminal position of the muscular contraction path and centric relation position increased.

[Primary clinical application of linear occlusion in immediate loading and implant-supported mandibular overdenture].

OBJECTIVE: To investigate clinical feasibility and technical features of immediate loading with linear occlusion on 2-implant-supported overdenture and to evaluate short-term effect of the treatment METHODS: Six edentulous patients with severe residual ridge resorption were enrolled. Two interforaminal implants were inserted for each patient and then immediate impressions were taken. Implant-supported bar-retained overdentures were restored for the patients within 24 hours. Clinical and radiographic examinations were conducted post-operative 1 week and 1, 3, 6, and 12 months. Thereafter at every 6 months the stability of implants, tissue situations around implants, radiographs and satisfaction level of patients were examined for each patient. RESULTS: Six cases and 12 implants were followed from 9 to 30 months. No implant was loosened or dropped. Sulculus bleeding index was 0-1 and probing depth of sulcus was less than 2 mm. The gingival tissues around the implants were healthy. Radiographic examination showed that bone resorption was less than 1 mm in the first year. The alveolar bone around the implants hasn't show obvious resorption stable height. Patients were satisfied with the implants. CONCLUSIONS: The results of this study indicate that immediate loading using linear occlusion on implant-supported bar-retained overdenture is predictable in some cases and can achieve satisfaction in the short-term service. Further study is needed to assess the long-term results.