Publications by authors named "Dale Howes"

8 Publications

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Dentoalveolar outcomes in maxillary reconstruction: A retrospective review of 85 maxillectomy reconstructions.

ANZ J Surg 2021 Jun 14. Epub 2021 Jun 14.

Department of Head and Neck Surgery, Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.

Background: Although microvascular free flaps are often used to reconstruct maxillary defects, dentoalveolar rehabilitation is arguably less common despite its importance to midface function and aesthetics. The aim of this study is to review the contemporary management of maxillary defects in a single quaternary referral institution to identify factors that assist or impede dentoalveolar rehabilitation.

Methods: A retrospective review of maxillary reconstructions performed between February 2017 and December 2020 was performed. Patient characteristics, defect classification, operative techniques, complications and dentoalveolar outcomes were recorded.

Results: A total of 85 maxillary reconstructions were performed in 73 patients. Of the 64 patients where dental rehabilitation was required, 31 received a functional denture (48%) with 24 (38%) being implant-retained. Significant predictors of successful rehabilitation included the use of virtual surgical planning (VSP; 86% vs. 25%, p < 0.001), preoperative prosthodontic assessment (82% vs. 21%, p < 0.001), prefabrication (100% vs. 40%, p = 0.002) and use of the zygomatic implant perforator flap technique (100% vs. 39%, p = 0.001). Preoperative prosthodontic consultation was associated with 21-fold increase in the odds of rehabilitation (odds ratio 20.9, 95% confidence interval 6.54-66.66, p < 0.005).

Conclusion: Preoperative prosthodontic evaluation, VSP and reconstructive techniques developed to facilitate implant placement are associated with increased dental rehabilitation rates. Despite using an institutional algorithm, functional dentures are frequently prevented by factors including soft tissue constraints, disease recurrence and patient motivation.
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http://dx.doi.org/10.1111/ans.17001DOI Listing
June 2021

Maxillofacial reconstruction with prefabricated prelaminated osseous free flaps.

ANZ J Surg 2021 03 6;91(3):430-438. Epub 2021 Jan 6.

Department of Head and Neck Surgery, Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.

Background: The prefabricated fibula flap is an advanced method of occlusal-based reconstruction that combines placement of osseointegrated dental implants with prelamination, using a split skin graft on the fibula, weeks prior to the definitive reconstruction. This approach is resource intensive but has several advantages including eliminating the delay from reconstruction to dental rehabilitation.

Methods: A retrospective cohort study of all prefabricated fibula flaps used for mandible and maxillary reconstruction from 2012 to 2020 was performed. Outcome measures were implant survival, implant utilization and functional dental rehabilitation.

Results: A total of 17 prefabricated fibula flaps were performed including two analogue and 15 digital plans. There were nine maxillary and eight mandibular reconstructions, of which 11 were primary and seven were secondary. There were no free flap failures. A total of 65 implants were placed (average 3.8, median 3 implants). There was one implant failure at 6 years giving a 1.5% failure rate. There was 91% implant utilization and 94% functional dental rehabilitation.

Conclusion: The prefabricated fibula flap provides outstanding dental rehabilitation in well-selected patients.
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http://dx.doi.org/10.1111/ans.16541DOI Listing
March 2021

Occlusal-based planning for dental rehabilitation following segmental resection of the mandible and maxilla.

ANZ J Surg 2021 03 27;91(3):451-452. Epub 2020 Nov 27.

Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.

Reconstruction of the maxilla and mandible incorporating a dental prosthesis supported by dental implants is a complex process but has tremendous benefit to patient rehabilitation following ablative procedures. This study presents a protocol that can be used to aid other institutions to provide the highest standard of reconstruction.
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http://dx.doi.org/10.1111/ans.16441DOI Listing
March 2021

Angled Implant Design to Accommodate Screw-retained Implant-supported Prostheses.

Authors:
Dale Howes

Compend Contin Educ Dent 2017 Jul;38(7):458-463; quiz 464

Professor and Head, Department of Oral Rehabilitation, School of Oral Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Co-founder, P-I Brånemark Institute of South Africa.

Anatomical constraints at implant sites often precipitate a conflict between surgical and prosthodontic prerequisites for screw retention of implantsupported prostheses. This article discusses use of a dual-axis implant designed to help clinicians overcome these challenges by facilitating accuracy of surgical placement and prosthetic simplicity, as well as improving biomechanics and enhancing esthetics.
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July 2017

A comparison of the accuracy of polyether, polyvinyl siloxane, and plaster impressions for long-span implant-supported prostheses.

Int J Prosthodont 2014 Sep-Oct;27(5):433-8

Purpose: The purpose of this study was to compare the capacity of different impression materials to accurately reproduce the positions of five implant analogs on a master model by comparing the resulting cast with the stainless steel master model. The study was motivated by the knowledge that distortions can occur during impression making and the pouring of casts and that this distortion may produce inaccuracies of subsequent restorations, especially long-span castings for implant superstructures.

Materials And Methods: The master model was a stainless steel model with five implant analogs. The impression materials used were impression plaster (Plastogum, Harry J Bosworth), a polyether (Impregum Penta, 3M ESPE), and two polyvinyl siloxane (PVS) materials (Aquasil Monophase and Aquasil putty with light-body wash, Dentsply). Five impressions were made with each impression material and cast in die stone under strictly controlled laboratory conditions. The positions of the implants on the master model, the impression copings, and the implant analogs in the subsequent casts were measured using a coordinate measuring machine that measures within 4 μm of accuracy.

Results: Statistical analyses indicated that distortion occurred in all of the impression materials, but inconsistently. The PVS monophase material reproduced the master model most accurately. Although there was no significant distortion between the impressions and the master model or between the impressions and their casts, there were distortions between the master model and the master casts, which highlighted the cumulative effects of the distortions. The polyether material proved to be the most reliable in terms of predictability. The impression plaster displayed cumulative distortion, and the PVS putty with light body showed the least reliability.

Conclusions: Some of the distortions observed are of clinical significance and likely to contribute to a lack of passive fit of any superstructure. The inaccuracy of these analog materials and procedures suggested that greater predictability may lie in digital technology.
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http://dx.doi.org/10.11607/ijp.4035DOI Listing
November 2014

The three-dimensional casting distortion of five implant-supported frameworks.

Int J Prosthodont 2009 May-Jun;22(3):248-50

Department of Prosthodontics, School of Oral Health Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.

The aim of this study was to assess three-dimensional distortion in cast full-arch, screw-retained titanium implant frameworks. A conventional commercial laboratory one-piece casting was used implementing the lost-wax technique. Five wax patterns were fabricated on a die-stone cast poured from a plaster impression of a five-implant brass analog. A reflex microscope was used to determine the three-dimensional casting error. Significant differences were found in distortion between wax patterns and castings, which, given the need to keep within 150 microm of misfit for passivity, were larger than the wax frameworks by between 416 and 477 microm. The greatest distortion occurred at the terminal implant abutments and in the vertical dimensions, but the distortion was inconsistent, indicating its three-dimensional nature. It is doubtful whether any conventionally cast titanium framework can be made to the degree of accuracy required to fit passively on its abutments because of the multiple variables inherent in this process.
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September 2009

A protocol for maxillary reconstruction following oncology resection using zygomatic implants.

Int J Prosthodont 2007 Sep-Oct;20(5):521-31

Division of Maxillo-Facial and Oral Surgery, Department of Surgery, University of the Witwatersrand, Johannesburg, South Africa.

The purpose of this clinical report is to present a surgical and prosthodontic reconstructive protocol for 20 patients who underwent maxillary resection following malignancy to the head and neck region. This protocol was developed over a period of 7 years while treating a series of 20 maxillary resections due to oncology. Patients were reconstructed prosthodontically using fixed-removable overdentures or fixed prostheses, with and without separate obturators. The treatment protocol includes a comprehensive diagnostic phase, resection surgery with immediate implant placement and temporary obturation, post resection evaluation, and prosthodontic rehabilitation. Treatment periods ranged from 6 to 96 months and success was evaluated using strict clinical, radiologic, esthetic, and functional criteria. Postsurgical radiology was undertaken at 6 monthly intervals. Almost all maxillary defects resulting from anatomic disruption of the maxillofacial complex can be well rehabilitated functionally and esthetically using this protocol in conjunction with standard implantology and fixed/fixed-removable prosthodontic principles. This protocol simplifies the rehabilitation and management of these defects by reducing surgical intervention, hosptilization, postoperative morbidity and treatment time, and prosthodontic procedural complications.
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November 2007

Surgical modifications to the Brånemark zygomaticus protocol in the treatment of the severely resorbed maxilla: a clinical report.

Int J Oral Maxillofac Implants 2003 Mar-Apr;18(2):232-7

Division of Maxillofacial and Oral Surgery, Department of Surgery, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.

Purpose: The Zygomaticus dental implant, designed by Nobel Blocare, was developed for the treatment of the severely resorbed maxilla. Brånemark has reported an overall success rate of 97.6% with the placement of 183 implants over the last 12 years. The purpose of this article was to present a modification to the original Brånemark surgical approach to achieve better access and optimal Implant placement.

Materials And Methods: There are parameters within the patient's resorbed skeletal frame that guide the surgical placement of the currently used Implant However, there are shortcomings in the current surgical protocol. This report describes a simplified surgical approach in 45 patients (77 implants) using an Implant with a modified head angulation of 55 degrees and a placement appliance to assist the surgeon in placing the implant as close to the crest of the edentulous ridge as possible.

Results: The placement appliance identifies accurately the anatomic constraints of the resorbed skeletal frame that limit implant placement. This, together with the modified surgical protocol, has resulted in improved access and in ideal positioning of the restorative head.

Discussion: The present technique allows restorative clinicians to achieve a more ideal restorative result In the posterior maxillary alveolus using the zygomatic implant, while reducing the buccal cantilever, improving tongue space, and access for maintenance.

Conclusion: By placing the implant closer to the crest of the alveolar ridge using the placement appliance and an implant with a 55-degree head, the emergence of the restorative head and resultant buccal cantilever can be reduced by as much as 20%.
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June 2003
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