Patient-reported outcomes in patients with severe maxillary bone atrophy restored with zygomatic implant-supported complete dental prostheses: a systematic review.

Introduction and Objective: Zygomatic implants (ZI) offer a good and predictable alternative to reconstructive procedures of atrophic maxillae. The main objetive of this systematic review was to assess the effect of rehabilitation with zygomatic implants on patient's quality of life (QLP) using Patient Reported Outcomes Measures (PROMs).Materials and Methods: This review followed PRISMA guidelines. An automated electronic search was conducted in four databases supplemented by a manual search for relevant articles published until the end of January 2021. The Cochrane Collaboration Risk of Bias tool and the Newcastle-Ottawa Quality Assessment Scale were used to assess the quality of evidence in the studies reviewed.Results: General findings of this systematic review showed substantial increases in Oral health-related quality of life (OHRQoL) among patients restored with ZI and high scores in terms of general satisfaction, especially in chewing ability and esthetics. An overall survival rate of ZI was 98.3% after a mean follow-up time of 46.5 months was observed. Occurrence of 13.1% biological complications and 1.8% technical complications were reported.Conclusions: Patients rehabilitated with zygomatic implant-supported complete dental prostheses showed substantial improvements in OHRQoL and general satisfaction with the treatment received.

Zygomatic implant survival in 9 ectodermal dysplasia patients with 3.5- to 7-year follow-up.

OBJECTIVE: Ectodermal dysplasia syndrome is a complex group of genetic disorders identified by the abnormal development of the ectodermal structures. The aim of this retrospective clinical case series report was to evaluate the outcomes of the ectodermal dysplasia syndrome patients that underwent zygomatic implant surgery. MATERIALS AND METHODS: A total of 9 ectodermal dysplasia syndrome patients aged between 21 and 56 years (mean age 36.8) with severely atrophic maxilla were included in this study. All the patients were treated with a total of 19 zygomatic implants. The mean follow-up of the patients was 55 months (with a range of 44-84 months). The implant survival rate was evaluated as a primary outcome. The intra- and postoperative complications were evaluated as additional criteria for success. RESULTS: The overall implant survival rate was 100% without any complications. Final or provisional prosthesis was delivered on the same day of surgery, which resulted in an improvement of the quality of life of the patients. CONCLUSION: According to the results of this study, zygomatic surgery can be considered as a viable and safe alternative to conventional treatment modalities for oral rehabilitation of ectodermal dysplasia syndrome patients.

The Mini-Zygoma Reduction Surgery: A Simple and Reliable Approach for Mid-Face Narrowing.

Reduction of mid-face width is a major concern in Asian facial contouring surgery, and some patients want their mild or borderline problems to be improved in a minimally invasive manner. The authors' mini-zygoma reduction surgery technique is indicated for patients who seek both minimal invasiveness and reliability. Patients presenting with a wide mid-face and isolated zygomatic arch protrusion without severe zygomatic body prominence were included into the study. All surgeries are performed under local anesthesia and on an outpatient basis. Through temporal and sideburn incisions, complete osteotomy was performed on the temporal process of the zygomatic body and just in front of the anterior tubercle of the zygomatic arch. After transposition to a proper inward position, the osteotomized segment was rigidly fixed on the zygomatic arch with metal fixtures. All surgeries were successfully performed without excessive blood loss or any unpredicted events. Over the 6 to 18-month follow-up period, most patients were satisfied with the aesthetic results of the surgery, the rapid recovery, and the minimal postoperative swelling. Even with a 1-point fixation, the segment remained stable and did not show displacement of the bony segment. In patients showing a minimal zygomatic arch prominence and seeking minimally invasive surgery, the proposed technique can be a proper surgical option with reliable and predictable results. The surgery can be performed without general anesthesia and on an outpatient basis, thereby resulting in prompt postoperative recovery. Predictability and reliability is assured with rigid fixation with a metal fixture on the zygomatic arch.

Comparison of Effects of Pulsed Electromagnetic Field Stimulation on Platelet-Rich Plasma and Bone Marrow Stromal Stem Cell Using Rat Zygomatic Bone Defect Model.

BACKGROUND: Reconstruction of bone defects that occur because of certain reasons has an important place in plastic and reconstructive surgery. The objective of the treatments of these defects was to reinstate the continuity of tissues placed in the area in which the defect has occurred. In this experimental study, the effect of pulsed electromagnetic field stimulation on platelet-rich plasma (PRP) and bone marrow stromal cell, which propounded that they have positive impact on bone regeneration, was evaluated with the bone healing rate in the zygomatic bone defect model enwrapped with superficial temporal fascia. METHODS: After creating a 4-mm defect on the zygomatic bone of the experiments, the defect was encompassed with a superficial temporal fascial flap and a nonunion model was created. After surgery, different combinations of the PRP, bone marrow stromal cell, and electromagnetic field applications were implemented on the defective area. All the experiments were subjected to bone density measurement. RESULTS: The result revealed that the PRP and pulsed electromagnetic field implementation were rather a beneficial and an effective combination in terms of bone regeneration. CONCLUSIONS: It was observed that the superficial temporal fascial flap used in the experiment was a good scaffold choice, providing an ideal bone regeneration area because of its autogenous, vascular, and 3-dimensional structures. As a result, it is presumed that this combination in the nonhealing bone defects is a rather useful treatment choice and can be used in a reliable way in clinical applications.

One-stage treatment to osteochondroma of the coronoid process and secondary facial asymmetry with coronoidectomy and reduction malarplasty: a case report and literature review.

PURPOSE: This study summarizes the literature concerning osteochondroma of the mandibular coronoid process and presents a case of 1-stage treatment for this condition and concomitant facial asymmetry. MATERIALS AND METHODS: A 20-year-old man presented with osteochondroma of the mandibular coronoid process. Radiologic images showed a mushroom-shaped coronoid growth inside the zygomatic arch with outward expansion. Coronoidectomy and reduction malarplasty were performed in 1 stage. The literature on osteochondroma of the mandibular coronoid process since 1943 was reviewed concerning etiology, pathogenesis, clinical characteristics, diagnosis, and treatment. RESULTS: At 20-month follow-up, the patient achieved markedly improved joint function and a symmetric facial appearance after excision of the osteochondroma. CONCLUSION: Coronoidectomy combined with simultaneous reduction malarplasty could be an alternative and promising method to treat osteochondroma of the coronoid process with secondary facial asymmetry.

A new approach to aesthetic maxillofacial surgery: surgical treatment of unilateral exophthalmos due to maxillary sinus mucocele.

Maxillary sinus mucocele, known as a rare condition, can cause major therapeutic difficulties, especially when it invades the orbit leading to exophthalmia. Treatment is very difficult because the eye globe has to be repositioned, and the facial symmetry needs to be reconstructed as a result of malar bone invasion. This article reports the case of a 54-year-old patient with unilateral exophthalmia caused by the evolution of a maxillary mucocele that extended toward the orbit after destroying the malar bone and the orbital floor. The treatment consisted of a 1-step restoration of both the orbit floor and the malar bone using a temporomandibular flap composed of 2 bone fragments. Lipostructure and a titanium mesh to reconstruct the calvarial defect were necessary to restore facial aesthetics after placing back the eye globe in its initial site. After surgery, the patient followed a complex rehabilitation program including massage kinesiotherapy and psychological consultation and support. These had an essential contribution to the successful final outcome in terms of psychological impact, functionality, and aesthetics.

A national survey of oral and maxillofacial surgeons' attitudes towards the treatment and dental rehabilitation of oral cancer patients.

AIMS: To investigate the attitudes of maxillofacial surgeons in the treatment and dental rehabilitation of oral cancer patients in the UK. MATERIAL AND METHODS: The survey was conducted by postal questionnaires with 17 close-ended questions. A total of 229 questionnaires were sent to members of the British Association of Oral and Maxillofacial Surgeons over a one week period. A follow-up was sent if a reply was not received within 12 weeks. These results were compared to a similar study that was carried out approximately 15 years ago. RESULTS: The response rate was 65.5% (150/229). Overall 62% of respondents (92/150) carried out maxillary resections, which represents a decline of 23% on the previous study. There has been an increase in surgeons reconstructing the maxillary defect from 38% in the 1995 study to 91% in the present study. Ninety-eight percent of respondents had their patients seen in a multidisciplinary team (MDT) clinic, but in only 30% of the cases was a restorative dentist present on these clinics. There has been an improvement in the accessibility of a restorative dentist for this patient cohort, from 65% to 90%. The use of implants for dental rehabilitation post-cancer surgery has increased from 43% to 93%. CONCLUSION: This study highlights the changes in the dental and oral rehabilitation of patients undergoing resective surgery for oral cancer and especially those undergoing a maxillectomy procedure. It illustrates the increased use of implants for post-surgery rehabilitation and shows the different trends in which these implants are placed. An important aspect of this study is the input of the dental team. Current national guidelines state that a consultant restorative dentist needs to be a member of the MDT; this survey shows that this was the case in only 30% of responses.

Extension of the one-piece orbitozygomatic frontotemporal approach to the glenoid fossa: cadaveric study.

OBJECTIVE: Resection of the glenoid fossa has been described as part of cranial approaches to the clivus and subtemporal approaches. However, radical resection carries a significant risk of postoperative temporomandibular joint dysfunction. We examine a simple variation of our previously described one-piece frontotemporal orbitozygomatic (FTOZ) osteotomy that adds en bloc resection of the root of the zygomatic arch and a portion of the glenoid fossa. METHODS: Five cadaveric fixed heads injected with colored silicone underwent an FTOZ osteotomy that extended to the root of the zygomatic arch and glenoid fossa. RESULTS: A step-by-step guide to the surgical technique is described, with illustrations to depict the glenoid fossa keyhole and bony cuts that free the zygomatic arch and portions of glenoid fossa. The first cut was made through the posterior root, and the second cut was made through the anterior root of the zygomatic arch. CONCLUSION: In this cadaveric study, extension of the one-piece FTOZ approach included the posterior root of the zygoma and the lateral part of the glenoid fossa. En bloc resection of the glenoid fossa and root of the zygomatic arch, together with the FTOZ osteotomy, facilitated reconstruction of the temporomandibular joint and increased the amount of exposure obtained with this FTOZ osteotomy. Comprehensive understanding of functional outcomes awaits further clinical study.

Quantitative analysis of exposure of staged orbitozygomatic and retrosigmoid craniotomies for lesions of the clivus with supratentorial extension.

OBJECTIVE: A two-stage approach using orbitozygomatic (OZ) and retrosigmoid (RS) craniotomies is one option for the management of petroclival lesions with supratentorial extension. The goal of this study was to investigate the supratentorial and infratentorial exposures of the clivus obtained through this staged approach. METHODS: Formalin-fixed, silicon-injected specimens underwent stereotactic imaging. Six paired OZ and RS craniotomies were performed. Neuronavigation was used to determine the areas and limits of exposure and to plot these areas on three-dimensional reconstructions of the skull base. RESULTS: The mean area of exposure of the parasellar region and clivus through the OZ craniotomy was 640 +/- 75 mm. Visualization of the parasellar region, cavernous sinus, and upper cranial nerves was achieved. The ventral brainstem corresponding to the cranial quarter of the clivus was visualized. The mean area of exposure of the clivus and petrous bone through the RS was 1930 +/- 250 mm. In the cranial quarter of the clivus, there was a small region of overlap in exposure between the two craniotomies. The limits of exposure are described. CONCLUSION: OZ and RS craniotomies provide complementary exposure with limited redundancy. Significant visualization of the parasellar region, clivus, and surrounding bony landmarks is obtained. The primary limitation is exposure of the contralateral half of Zones II and III of the clivus. This strategy represents a reasonable option for accessing paracentral petroclival lesions with a supratentorial extension.

Morphology of autogenous bone graft and castor oil polyurethane in the infraorbital rim of rabbits: a comparative study / Estudo morfológico comparativo do enxerto ósseo autógeno e polímero de mamona em rebordo infra-orbitário de coelhos

PURPOSE: Morphological study comparing castor oil polyurethane and autogenous bone graft to repair bone defect in zygomatic bone of rabbits. METHODS: Twenty-four adult, male New Zealand rabbits were randomly distributed between two groups of twelve. Bone defects of 5mm in diameter were cut through the zygomatic bone and filled with polyurethane discs in the experimental group or autogenous bone harvested from the tibia in the control group. Animals were sacrificed after 30, 60 or 90 days, and the zygomatic bones were macro- and microscopically analyzed. Student's, Fisher's, chi-squared and McNemar's tests were used for statistical analysis. RESULTS: Both the castor oil polyurethane and the autograft adapted well to the defect, with no need for fixation. Fibrous connective tissue encapsulated the polyurethane, but no inflammation or giant cell reaction was observed. Acidophilic and basophilic areas were observed inside the micropores of the polyurethane, suggesting cell nuclei. After 90 days, bone repair with a lamellar pattern of organization was observed in the control group. CONCLUSION: The castor oil polyurethane was biocompatible and did not cause inflammation. It may be considered an alternative to fill bone defects.

OBJETIVO: Estudo morfológico comparativo do implante de poliuretana de mamona e enxerto ósseo autógeno em defeito ósseo padrão em osso zigomático de coelhos. MÉTODOS: Vinte e quatro coelhos Nova Zelândia, machos, adultos, foram distribuídos aleatoriamente em dois grupos de 12. Defeitos de 5mm de diâmetro, perenes, foram confeccionados em osso zigomático e preenchidos com discos pré-fabricados de poliuretana no grupo experimento ou osso autógeno extraído da tíbia no grupo controle. Os animais foram sacrificados após 30, 60 e 90 dias e as peças anatômicas foram avaliadas macro e microscopicamente. Foram utilizados os testes de Student, Fisher,qui-quadrado e McNemar para a análise estatística dos resultados. RESULTADOS: A poliuretana e o osso autógeno se adaptaram ao defeito sem necessidade de fixação. Houve formação de tecido conjuntivo fibroso envolvendo a poliuretana, sem reação inflamatória ou presença de células gigantes. Verificaram-se áreas acidófilas e basófilas nos poros do material implantado, sugestivas de núcleos celulares. No grupo controle, observou-se aos 90 dias o reparo ósseo de padrão lamelar clássico. CONCLUSÃO: A poliuretana de mamona foi biocompatível e não causou reação inflamatória deletéria. Pode ser uma alternativa para o preenchimento de defeitos ósseos.

Morphology of autogenous bone graft and castor oil polyurethane in the infraorbital rim of rabbits: a comparative study.

PURPOSE: Morphological study comparing castor oil polyurethane and autogenous bone graft to repair bone defect in zygomatic bone of rabbits. METHODS: Twenty-four adult, male New Zealand rabbits were randomly distributed between two groups of twelve. Bone defects of 5mm in diameter were cut through the zygomatic bone and filled with polyurethane discs in the experimental group or autogenous bone harvested from the tibia in the control group. Animals were sacrificed after 30, 60 or 90 days, and the zygomatic bones were macro- and microscopically analyzed. Student's, Fisher's, chi-squared and McNemar's tests were used for statistical analysis. RESULTS: Both the castor oil polyurethane and the autograft adapted well to the defect, with no need for fixation. Fibrous connective tissue encapsulated the polyurethane, but no inflammation or giant cell reaction was observed. Acidophilic and basophilic areas were observed inside the micropores of the polyurethane, suggesting cell nuclei. After 90 days, bone repair with a lamellar pattern of organization was observed in the control group. CONCLUSION: The castor oil polyurethane was biocompatible and did not cause inflammation. It may be considered an alternative to fill bone defects.

Zygoma implant-supported midfacial prosthetic rehabilitation: a 4-year follow-up study including assessment of quality of life.

OBJECTIVE: Successful prosthetic rehabilitation is crucial for quality of life in cases of large maxillary defects when surgical reconstruction is not advisable because of general health or patient refusal. For this purpose, the extended indications for Zygomaticus fixtures in different defect types were evaluated. PATIENTS AND METHODS: Twelve patients received 28 zygoma implants and 23 dental implants (if a segment of alveolar process was available) and were followed-up 14-53 months. Zygoma implants were positioned classically in the maxillary molar region and to reduce leverage, a premolar and a canine position was developed. The quality of life was assessed by a validated questionnaire after complete rehabilitation. RESULTS: Cumulative zygoma implant survival was 82%. Three losses occurred because of persistent infection and gradual loosening. Lost implants were immediately replaced in adjacent bone. Insufficient implant length within soft tissue reconstructions was prone to chronic infection by pocketing and recurrent overgrowth of granulating tissue. Longer implants were free of soft tissue inhibition, yet prone to overloading and high leverage in cases when no anterior alveolar process and dental implants were present. Zygoma implant success was therefore 71%, including the new premolar and canine Zygomaticus fixture-position. Periotest values increased from 0 to +7 to the fourth year, peri-implant bleeding and plaque index were decreasing from 56% to 0% and 33% to 0%, respectively, and good general quality of life with the priorities on chewing and activity was noted. CONCLUSION: Zygoma implants can reliably anchor the midfacial maxillary prostheses and enable a quality of life comparable with autologous maxillary reconstruction. They can be replaced immediately if local infection or loosening should occur. A premolar and canine position reduce leverage when no anterior alveolar process is present. The patient can alternatively be provided with dental implants.

Rehabilitación con implantes del maxilar posterior atrófico / Implant rehabilitation of the posterior atrophic maxilla

El tratamiento del sector posterior del maxilar atrófico puede obligar al cirujano a recurrir a técnicas quirúrgicas complejas. Se presenta la descripción de las técnicas de implantes pterigoideos y cigomáticos que tiene como objetivo la rehabilitación posterior del maxilar sin recurrir a injertos óseos. Se describe la técnica, sus indicaciones y se revisan series presentadas en la literatura. (AU)

Bone gap healing in the dog using recombinant human bone morphogenetic protein-2.

PURPOSE: This study investigated bone gap healing in a zygomatic arch defect using recombinant human bone morphogenetic protein-2 (rhBMP-2; Genetics Institute, Andover, MA) in an absorbable collagen sponge (ACS) carrier. METHODS: Zygomatic arch osteotomies were completed 15 mm apart and the arch was mobilized in 6 adult female mongrel dogs. The segment was then repositioned laterally 8 to 10 mm and secured with a titanium reconstruction plate. Bone gaps in either the right or left arches received rhBMP-2, with the contralateral side being left empty in 4 animals and the defects received buffer/ACS without rhBMP-2 in 2 animals as controls. Submentovertex radiographs were taken immediately postoperatively and every 4 weeks until killing at 12 weeks. RESULTS: Clinical evaluation indicated no significant differences in the degree of inflammation between the groups. However, the rhBMP-2 sites were found to be firm on palpation, in contrast to a soft tissue defect palpated in the control sites. Radiographic examination showed significant bone formation in all rhBMP-2 grafted sites as early as 4 weeks. The radiopacity of the bone continued to increase over the time of this study. Five of six control sites did not show bone formation through the course of this study. In addition to lack of bone formation, 5 of 6 control sites showed collapse of the repositioned arch. All arches in the rhBMP-2 sites remained in their lateral position and formed bone in the gaps. In 2 animals, bone formation moderately exceeded the confines of the gap, and in 2 animals excessive bone formation occurred. CONCLUSIONS: This study confirms that rhBMP-2 has the potential to be used to stimulate bone gap healing in the craniofacial complex.

Hydroxyapatite paste (BoneSource) used as an onlay implant for supraorbital and malar augmentation.

This study was designed to evaluate hydroxyapatite paste (BoneSource; Leibinger Corp., Dallas, TX) as an alloplastic implant for supraorbital and malar augmentation. Ten male Sprague-Dawley rats had cylindrical onlay implants made of the hydroxyapatite cement placed above their left orbits on the supraorbital rim. Size-matched Medpor implants were placed similarly on the right side. To test the utility of this new material in the midface, hydroxyapatite paste and Medpor implants were also placed in the right malar regions of a different set of rats. The implants were left in situ for 6 months and examined for evidence of bone ingrowth, infection, migration, resorption, and detrimental effects on the surrounding tissue. All hydroxyapatite cement implants provided excellent soft tissue projection and demonstrated steadfast adherence to the adjacent bone. The surface of the hydroxyapatite implant in contact with the native bone demonstrated evidence of native bony ingrowth into approximately 12% of the implant. There was no evidence of implant migration or gross infection. There was no bony resorption below the hydroxyapatite paste, but four of the Medpor implants showed evidence of this in the underlying bone. Only one negative aspect to the use of hydroxyapatite cement paste as an onlay implant was identified. Two of the supraorbital and one of the malar hydroxyapatite implants had approximately 20 to 25% volume loss during the experimental period (P = 0.05). Overall, the vast majority of the implants retained their original form. We concluded that hydroxyapatite paste may possibly be used to effectively augment bone in the supraorbital and malar regions. Its biocompatibility, excellent bony adherence, and tendency to be replaced by natural bone may make it suitable for the aesthetic patient. The possible resorptive aspects of the material need to be evaluated further.

Treacher Collins syndrome: early surgical treatment of orbitomalar malformations.

In the past various materials have been used for the correction of the malar bone defect, such as cartilage, dermis fat, silicone, autograft, homograft, xenograft, and free bone transplantation. The disadvantages of inorganic implants are well known: dislocation, extrusion, and capsular contraction. The bony autograft has no growth potential, and children may need several complementary corrections. None of these procedures is totally satisfactory. To solve these problems malar reconstruction is performed with the help of a temporal bone flap. Two varieties of these flaps have been described: one anteriorly with a muscular pedicle vascularized by the deep temporal artery and one posteriorly with a galeal pedicle vascularized by the superficial temporal artery. The main advantage of an osteomuscular flap is the survival of bone once it has been transferred. The second advantage is related to the osteogenic potential of the cambium layer of the periosteum, which may prove to be an ongoing concern. Our series of patients includes 20 children. Correction of the eyelid coloboma was obtained by transposition and advancement of a superior palpebral flap.

Temporal and malar-zygomatic reduction and augmentation.

The temporal fossa, zygomatic arch, and malar-midface should be considered jointly when augmentation of the temporal area or reduction of the zygomatic arch are to be carried out. These anatomic areas relate so closely to one another that altering one affects the other. In addition, augmentation of the malar-midface area may be done if one of the other two procedures is to be considered, or if a brow lift, subperiosteal face lift, or other reason for using a coronal incision exists. Use of the coronal incision for malar augmentation is probably not justified because of the large amount of surgery required in spite of the lesser morbidity associated with this approach in terms of amount of infections, lip stiffness, and hypesthesia. Planning a surgical procedure must be done in the office, by examining the patient at eye level to determine the amount of zygomatic arch reduction and the amount of temporal fossa augmentation necessary. Similarly, the three zones of the malar-midface complex must be assessed, with the amount of augmentation of each zone determined prior to the day of surgery. The surgical procedure is then executed through a coronal incision, with the dissection extending down to the zygomatic arch. If the temporal muscle is to be elevated out of its fossa, it is cut on its anterior, superior, and posterior edges, elevating it out of its fossa so that a Proplast implant, typically 3 to 4 mm thick and finely tapered on its superior and posterior edges, with suturing done anteriorly, may be inserted. The muscle is then resutured to its aponeurosis on all three edges. If the zygomatic arch and malar-midface area are to be approached, the dissection is carried to the deep and superior edge of the zygomatic arch, and the periosteal elevator is used to elevate the soft tissue off the lateral and inferior edge. The arch and malar-midface are cleared of soft tissue, extending the tunnel to the upper buccal sulcus. The arch is then reduced with a contouring burr to the thinness desired. Alternatively, the malar-midface area may be augmented with synthetic material precisely positioned, with a suture around the zygomatic arch, holding it in position as measured from the lateral orbital rim. The incision in the temporal fascia is then resutured, and the coronal incision is closed.(ABSTRACT TRUNCATED AT 400 WORDS)