Polyetheretherketone computer-aided design and computer-aided manufacturing framework for All-on-Four mandibular full-arch prosthesis: 3 Years' retrospective study of peri-implant soft tissue changes and ridge base relationship.

PURPOSE: This study was conducted to evaluate the clinical peri-implant soft tissue changes during the first year after occlusal loading and the ridge base relation after 3 years for mandibular computer-aided design and computer-aided manufacturing (CAD-CAM) screw-retained implant-supported hybrid prosthesis of polyetheretherketone (PEEK) framework utilized with All-on-Four treatment concept. MATERIALS AND METHODS: Sixteen completely edentulous patients were rehabilitated by four implants following the All-on-Four protocol. After 3 months, the definitive prosthesis was constructed to be a screw-retained CAD-CAM milled framework from the modified PEEK (BioHPP), bonded to polymethylmethacrylate teeth and a pink shaded indirect light-polymerized nanofilled composite resin imitating the soft tissues. Peri-implant soft tissue changes regarding plaque, bleeding, gingival scores, and probing depth were evaluated at prosthesis insertion (T0), 6 months (T1), and 12 months (T2) after insertion. Also, monitoring of the ridge base relation was performed using cone beam computed tomography at time of insertion (T0), and 1 year (T1), 2 years (T2), and 3 years (T3) after mandibular fixed detachable All-on-Four framework insertion. Using Shapiro-Wilk tests using SPSS® software version 22 (SPSS Inc., Chicago, IL), all clinical data were nonparametric, while the ridge base relation data were parametric. RESULTS: There were statistically significant differences regarding a plaque, gingival, and bleeding scores for all implants with the advancement of time. However, there was a statistically insignificant difference regarding probing depth in the posterior implants (p = 0.581). Regarding ridge base relation, there was a significant difference between observation times only in the anterior ridge area in between the two anterior implants (p = 0.011). CONCLUSIONS: Within the limitations of the study, the full-arch PEEK framework of fixed-detachable, hybrid prosthesis used with the All-on-Four concept for rehabilitation of mandibular edentulous arches is an acceptable treatment approach. Based on the stable ridge base relation posteriorly found in this study, less stress is distributed to the underlining bone due to the shock-absorbing ability of PEEK. Special considerations for frequent soft tissue follow-up and regular maintenance of oral hygiene measures are recommended.

Patient satisfaction and masticatory performance of zirconia bar compared to cobalt chromium bar retaining mandibular implant overdenture: A crossover study.

OBJECTIVES: The aim of this crossover clinical study was the evaluation and comparison of patient satisfaction and masticatory performance for patients rehabilitated with mandibular two implant overdentures retained with two different bar attachments: zirconia bar and cobalt chromium bar. MATERIAL AND METHODS: Twenty completely edentulous patients were divided into two equal groups: Group I (ZrO2), each patient received mandibular implant overdenture retained with CAD/CAM zirconia bar on two implants in the canine region, and Group II (Co-Cr), each patient received mandibular overdenture retained with conventional casted cobalt chromium metal bar. Patient satisfaction was measured with a survey questionnaire (PSQ-18), and masticatory performance was also evaluated with the two-colour mixing ability test after 3 months of overdenture insertion; then, each patient received a bar attachment from the other type and evaluations were repeated. RESULTS: Significant differences were observed regarding psychological acceptance (appearance), time, hygiene, undergo procedures, recommend procedures and the overall experience. In contrast, insignificant difference was observed regarding speech, chewing capacity, restorative procedures, complications and information prior to treatment. No significant difference was reported when comparing chewing performance between the two types of bar attachment. CONCLUSION: Within this clinical study limitations, patient satisfaction with zirconia bar was higher than Co-Cr bar in terms of appearance, time, hygiene, undergo procedures, recommend procedures and the overall experience. Zirconia can become a suitable alternative to cobalt chromium alloys as a bar attachment. Combining the advantages of implant supported overdenture, CAD/CAM zirconia bar as an attachment, a satisfactory non-metal prosthesis could be provided.

Impact of implants number and attachment type on the peri-implant stresses and retention of palateless implant-retained overdenture.

OBJECTIVES: To evaluate the impact of implants number and attachments type on the peri-implant stresses and retention of maxillary palateless implant-supported overdenture. MATERIALS AND METHODS: Four edentulous maxillary educational acrylic resin models were used. According to the implants number and type of attachment used, four groups were compared: Group I, 2-locator attachments in the canine area; Group II, 2- OT equator attachments in the canine area; Group III, 4-locator attachments in the canine, second premolar area and Group IV, 4-OT equator attachments in the canine, second premolar area. Implants retained palateless overdenture was constructed on each model. Four self-protected linear strain gauges were cemented on each implant. A digital loading device was used to apply compressive loads to measure the resulting peri-implant stresses. Forcemeter and Universal testing machines were used to test the retention of palateless overdenture. RESULTS: A significant difference between the same implant number and distribution with different attachments was found (P = 0.003, P = 0.020), respectively. Least stresses amount was found around the 4-implant locator palateless overdenture, while the highest was found around the 2-implant OT equator palateless overdenture. Nevertheless; the result was that 2-implant locator palateless overdenture recorded insignificant higher retentive forces than the 4-implant OT equator one. CONCLUSIONS: It can be concluded that the implant-retained palateless overdenture with four locator attachments is considered a promising treatment option regarding stress distribution. Using locator attachments, for implant-retained palateless overdenture with either two or four implants considering their superior retentive properties, is advantageous when compared to OT equator attachments.

Peri-implant Outcomes with Laser vs Nanosurface Treatment of Early Loaded Implant-Retaining Mandibular Overdentures.

PURPOSE: To compare peri-implant changes seen with two early loading protocols for modifying surface treatment of dental implants-one modifying the collar portion (Laser-Lok implant) and the other modifying the implant surface (nanosurface-treated implant). MATERIALS AND METHODS: Thirty-six completely edentulous patients were chosen for this research. Conventional complete dentures were constructed for all patients. Two implants were used for each patient corresponding to mandibular canines. The patients were classified into two groups. Eighteen patients in group 1 received 36 laser-collar-treated implants; 18 patients in group 2 received 36 nanosurface-treated implants. The implants were early loaded 2 weeks after implant insertion. The peri-implant outcome was evaluated using the following variables: (1) modified Plaque Index, (2) modified Bleeding Index, (3) probing depth, (4) implant mobility using the Periotest instrument, and (5) marginal bone loss as recorded at the time of the overdenture insertion and 6 and 12 months after insertion. RESULTS: At all times of the study, the differences between the groups were not significant with regard to peri-implant tissue changes around implants. CONCLUSION: Both the laser collar- and nanosurface-treated dental implants showed the same peri-implant tissue changes with the early loading protocol. This study found that both early loading protocols are reliable, with good implant stability.