Within-patient evaluation of chewing efficiency and maximum bite force of conventional dentures, fixed prostheses, and milled bar overdentures used for All-on-4 implant rehabilitation of atrophied mandibular ridges: A short-term randomized trial

PURPOSE

This crossover study aimed to evaluate chewing efficiency and maximum bite force (BF) of conventional dentures, fixed prostheses, and milled bar overdentures (MO) used for All-on-4 implant rehabilitation of atrophied mandibular ridges.

METHODS

Sixteen edentulous participants with resorbed mandibular ridges received new conventional dentures (CD, control). Four implants were inserted after 3 months in the mandible using the All-on-4 protocol and loaded immediately with acrylic prosthesis. In a crossover manner, each patient had either fixed restoration (FR, 12 occlusal units) or MO (14 occlusal units) randomly in a crossover study design. Chewing efficiency was evaluated using the mixing ability test. The hue deviation (HD) of two-colored gum was calculated after being chewed for 5, 10, 20, 30, and 50 masticatory cycles. Maximum BF was evaluated using a BF device. HD and BF were measured after using CD, FR, and MO prostheses.

RESULTS

For all groups, the highest HD (i.e., the lowest chewing efficiency) was noted with 5 strokes, followed by 10, 20, 30 strokes, and the lowest HD (i.e., the highest chewing efficiency) was noted with 50 strokes. For all number of chewing strokes, CD showed the highest HD, then FR, and MO recorded the lowest HD. The highest BF was observed with MO, then FR, and the lowest BF was noted with CD.

CONCLUSION

Within the limitations of this short-term investigation, both FR and MO used for All-on-4 implant rehabilitation of patients with resorbed mandibular ridges improve masticatory efficiency and maximum BFs compared to CD. However, MO was associated with significantly higher chewing efficiency and maximum BFs than fixed prosthesis.

Masseter muscle activity of conventional denture, fixed prosthesis, and milled bar overdenture used for All-on-4 implant rehabilitation: A within-subject study

PURPOSE

to examine the electromyographic (EMG) activity of the masseter muscles in patients with conventional dentures and compare it to EMG activity of fixed prosthesis, and milled bar overdentures used to rehabilitate mandibular atrophied ridges according to the All-on-4 concept.

METHODS

Eighteen edentulous subjects with atrophied mandibles received complete dentures (CD, control). After 3 months, four implants were installed between the mental foramina according to the "All-on-4" protocol and loaded immediately. After osseointegration, fixed prostheses (FPD) or milled bar overdentures (MBO) were given to the patients in random order. Primary (amplitude), and secondary (chewing rate, time of the masticatory cycle, time of masticatory burst, and masticatory time) outcomes were evaluated 3 months after using CD, FPD, and MBO. The evaluations were made during mastication of carrot (hard) and cake (soft) foods.

RESULTS

FPD and MBO were associated with a significantly higher (amplitude, time of masticatory cycle, and time of masticatory burst), and significantly lower (chewing rate and masticatory time) compared with conventional dentures. Primary and secondary outcomes did not differ between FPD and MBO. Carrot had significantly higher amplitude, chewing rate, time of masticatory burst, and masticatory time than cake, while cake had a significantly higher time of masticatory cycle than carrot.

CONCLUSIONS

Within limitations of this study, milled bar overdentures for All-on-4 implant rehabilitation of atrophied mandible is not less efficient than fixed prostheses in terms of electromyographic activity of the masseter muscle. Both prostheses significantly improve muscle activity, chewing rate, time of masticatory cycle, time of masticatory burst, and masticatory time compared with conventional dentures.

Implant-prosthetic rehabilitation of the edentulous mandible in a patient with Class III malocclusion and a retrognathic maxilla

Over the past few years, innovations in CAD/CAM processes allowed for manufacturing bar-retained constructions made of titanium or a Cobalt-chrome (CoCr) alloy to secure the position of overdentures. Here, the authors demonstrate the challenges of implant-prosthetic mandibular rehabilitation of a male 71-year-old patient with a reconstructed left-sided clefting congenital deformity and class III malocclusion with anterior crossbite and retrognathic maxilla. This case illustrates that the rehabilitation of an edentulous mandible with four intraforaminal implants and a CAD/CAM-fabricated bar with an overdenture can offer satisfactory prosthetic rehabilitation. In the present case, a bar-retained construction was the rehabilitation concept of choice, meeting the patient's request for restoration similar to the restorative concept in the maxilla and the correction of the reverse overjet in the anterior region.

Full Mouth Rehabilitation With All-on-Six Concept With Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) Milled Bar Retained Zirconia Prosthesis

Full-mouth rehabilitation, also known as full-mouth reconstruction or restoration, is the comprehensive process of restoring and rehabilitating the function, aesthetics, and health of all teeth in the upper and lower jaws. This involves a multidisciplinary approach, addressing issues such as occlusion (bite), tooth wear, tooth loss, and periodontal (gum) health to achieve optimal dental function and appearance. This treatment provides a stable and reliable solution for dental problems associated with the complete or partial loss of dental elements. This case report discusses the management of a 72-year-old male patient who came with a chief complaint of decayed, missing, and mobility of his teeth. His medical history included drug-regulated diabetes and chronic periodontitis, which remained a reason behind his deteriorating dental health. The treatment plan encompassed a comprehensive approach, starting with the full-mouth extraction and progressing to the placement of six implants in both the mandibular and maxillary arches for complete restoration. After allowing eight weeks for healing, the impressions for the implants were recorded with the polyvinyl siloxane material. The case demonstrates the application of the all-on-six concept; whereby full arch rehabilitation is possible with the strategic placement of six implants. By employing the latest in advanced computer-aided design/computer-aided manufacturing (CAD/CAM), a zirconia prosthesis that was retained on a milled bar was fabricated-yielding a very high degree of accuracy and excellent aesthetics in the restoration. Restorations with zirconium were done, as it is excellent in aesthetics and functioning. This article considers the importance of precision planning, correct implant placement, and advances in dental science and technology. Most importantly, the conclusion that can be drawn is that the end outcome of total rehabilitation with all-on-six should not only be an affirmation that difficult cases can be managed very well but also the patient's quality of life is improved by using the latest dental procedures.