Endoscopically-Assisted Zygomatic Implant Placement: A Novel Approach

Background

Zygomatic implants (ZIs) have been proposed as a valid alternative to advance bone-grafting procedures in the rehabilitation of the severe atrophied upper maxilla, with a reported overall success rate of more than 95 %. Otherwise, the use of the endoscope has been described for the treatment of maxillofacial trauma, orthognatic surgical procedures, sinonasal pathology, salivary gland disease, and TMJ internal derangement. A careful identification of anatomical landmarks is of utmost importance while trying to avoid potential complications during the insertion of ZIs. Several approaches for ZI insertion have been reported, such as the classical approach; the sinus slot technique; and the exteriorized approach.

Materials and Methods

The authors first introduce in the literature the endoscopically-assisted approach for the insertion of ZIs in the extremely severe atrophic maxilla.

Results

Optimal results in terms of ZIs positioning with no damage to surrounding structures were obtained.

Conclusions

By means of this new technique the surgeon may minimize the risk of complications related to the damage of neighbouring anatomic structures, such as orbital disruption or infraorbitary nerve damage, while ensuring an adequate drill positioning and angulation for the placement of one or two implants into the zygomatic bone.

     

Zygomatic implants: a critical review of the surgical techniques

Purpose

The purpose of the present study is to identify and describe the different surgical techniques for placement of zygomatic implants reported in the literature and discuss the differences between them.

Methods

An electronic search was undertaken in July 2011. The titles and abstracts from these results (n?=?130) were read for identifying studies, which reported different surgical techniques for placement of zygomatic implants, which resulted in 41 articles.

Results

Five different surgical approaches were identified: (1) the classical approach, (2) the sinus slot technique, (3) the exteriorized approach, (4) the minimally invasive approach by the use of custom-made drill guides, and (5) the computer-aided surgical navigation system approach. When the maxilla is severely resorbed, the concavity formed by the ridge crest is small, and the original classical technique should be used. When maxillary resorption generates a large concavity, it would be better to exteriorize the zygomatic implant. The externalized technique has fewer surgical steps than the classical and sinus slot methods, is less invasive, and reduces surgical time. It is recommended that utilization of the sinus slot technique together with the CT-based drilling guide would enhance the final results. Although the technique that uses the computer-aided surgical navigation system approach may produce an improved precision in the clinical procedure, its use is expensive, prolongs the operation time, and is limited to centers that have the necessary equipment for the surgery.

Conclusions

Preference for one technique over the other should take into consideration the concavity formed by the ridge crest, maxillary sinus, and region of implant insertion in the zygomatic bone.     

Immediate loading of overdentures: systematic review

Introduction

The goal of implant treatment is the formation of a direct bone–implant interface contact.

Purpose

This study aimed to evaluate the possibilities of immediate loading treatment for edentulous patients rehabilitated with mandibular and maxillary overdentures.

Material and methods

A literature review using the PubMed and BIREME databases between the periods of 1977 and 2011 was performed.

Results

From an initial yield of 218 titles, 78 articles were selected for text analysis, finally resulting in 23 studies (16 prospective, 6 prospective randomized, and 1 prospective multicenter) that met the inclusion criteria.

Conclusion

The immediate loading protocol through which the implants are subjected to occlusal function immediately after their placement was introduced to overcome this limitation.     

Protocol for mandibular reconstruction with zygomatic implants (zygomatic mandibular implant)

Introduction

This study describes a modified protocol using transmandibular zygomatic implants with immediate occlusal loading for the comprehensive dental rehabilitation of previously reconstructed mandibular defects and reports preliminary results of this modified protocol.

Materials and methods

Fifteen patients (6 female and 9 male), with a mean of age 40.26 years (range 12 to 68 years), had previously undergone immediate mandibular reconstruction using either autologous bone grafting, bone transport, or microvascular free-flap reconstruction for a variety of diagnoses. Transmandibular zygomatic implants were subsequently placed, depending on the type of defect. Implant stability was evaluated by insertion torque, percussion testing, and the implant stability quotient (ISQ). The patients were rehabilitated with an immediate provisional prosthesis. All patients’ records included pre and postoperative clinical examination, radiographs, CT scan, and photographic analysis. All patients were followed for a minimum of 36 months.

Results

All patients were dentally rehabilitated immediately with functional and esthetic hybrid dentures based on either acrylic or porcelain on a metal framework. Among all cases of transmandibular zygomatic implants, the ISQ was greater than 75, which allowed immediate prosthetic loading. The zygomatic implants were considered to be successful if they were asymptomatic with no clinical mobility and no sign of infection. We have also added new indications for placement of transmandibular implants in cases of sequelae of gunshot trauma, dentoalveolar defects, and complications of orthognathic surgery, partially edentulous and/or failure of prior mandibular reconstruction.

Conclusions

The zygomatic implant is an excellent immediate loading option for mandibular dental rehabilitation among patients with mandibular defects. According to our observation, immediate occlusal loading of transmandibular zygomatic implants has a very good potential for success.

     

Implant survival and patient satisfaction in completely edentulous patients with immediate placement of implants: a retrospective study

Background

This study evaluated full-arch rehabilitation of patients with immediately placed implants in terms of the cumulative implant survival rate, risk factors for implant failure, and patient satisfaction.

Methods

Time-to-event data of 52 completely edentulous jaws (370 implants) were collected using retrospective clinical chart review for the time period from 2008 to 2014. A conventional two stage approach for surgery was adopted to immediately placed implants in the maxilla, and immediate placement and immediate loading protocols for the mandible were followed. The study calculated the 7-year cumulative survival rates (CSR), and a Bayesian hierarchical Cox proportional hazard model was used to measure the effect of covariates. Patient satisfaction on chewing ability, esthetic appearance, and overall satisfaction was also measured with a face-to-face interview survey.

Results

Of the total 370 implants, 194 were immediate placement. Two delayed loading maxillary implants failed within the first year, and another one failed in the second year of loading. Two failures were recorded in the first year and one in seven years for the immediate loading mandibular implants. The 1-, 5-, and 7-year CSR of the 370 implants were 0.989 (0.979, 1.000), 0.986 (0.975, 0.998), and 0.978 (0.957, 0.999), respectively. Only the length of the implant affected implant failure (p?<?0.05); other patient characteristics, systemic diseases, implant diameter, immediate loading, and immediate placement, did not have an effect on implant failure rates. Patients reported a high degree of satisfaction regardless of their age group or length of the observation period.

Conclusions

Immediately placed implant had CSR as high as delayed placed implants, and 7-year CSRs of immediate loading were not significantly different from delayed loading. The procedure also had a high degree of chewing ability, esthetic appearance, and overall satisfaction. The study results suggested that the clinical procedures applied in this study to completely edentulous patients were acceptable rehabilitation procedures.

     

The single midline implant in the edentulous mandible: a systematic review

Objectives

The concept of a single midline implant retaining a complete mandibular denture is controversially discussed among experts. Studies are rare in the literature, and commonly accepted recommendations for this treatment options are not available. This systematic literature review was performed to give an overview over the current literature on the single midline implant therapy for the edentulous mandible and to reveal whether this treatment option might be an alternative to commonly accepted treatment modalities with more implants.

Methods

A review of the literature published until 24th of May 2013 was conducted to identify in vivo studies on the single midline implant concept with a mean follow-up time of at least 3 months.

Results

From the electronic search, 11 studies were finally included. After an observation period of 3–60 months, the implant survival rate ranged from 62.5 to 100 %. The most frequent prosthetic maintenance intervention was “activation of the matrix” followed by “repair of fractured denture base.”

Conclusions

The concept of one single midline implant to retain a mandibular complete denture can be an alternative, especially for elderly patients. Immediate loading of the implants should be avoided, and the way of integrating the matrix into the denture base should be carefully considered.     

Implant rehabilitation in patients with oral lichen planus: an overview

Objectives

Implant rehabilitation in oral lichen planus (OLP) is a major challenge for clinicians and patients. There is limited scientific evidence, primarily case reports and small case series. We conducted a literature review of data on the effectiveness and safety of implant rehabilitation in OLP patients.

Material and methods

We searched MEDLINE, Embase and Cochrane databases for articles on implant placement in OLP patients (searches from 1980 to 2011).

Results

Eight studies (41 OLP patients rehabilitated with 135 implants) met the inclusion criteria. Survival rate of implants was 94.8% over a mean follow-up of 56.5?months.

Conclusions

There is very limited evidence on the safety and benefits of implant placement in OLP patients. Implant loss appears not to be directly related to OLP, but linked to factors such as parafunctions, poor bone quality and marginal mandibular resection. The benefits and harms of using implants in people with OLP require thorough evaluation in properly designed randomised, controlled studies.

Clinical relevance

OLP is not an absolute contraindication for implant insertion and there is no increased risk of failure. Implants should be positioned only if mucosal signs and symptoms are in the remission phase. A careful oral hygiene and frequent follow-up are the main recommendations in OLP patients rehabilitated with implants.     

Oral rehabilitation with dental implants in irradiated patients: a meta-analysis on implant survival

Objectives

The aim of this comprehensive literature review is to provide recommendations and guidelines for dental implant therapy in patients with a history of radiation in the head and neck region. For the first time, a meta-analysis comparing the implant survival in irradiated and non-irradiated patients was performed.

Material and methods

An extensive electronic search in the electronic databases of the National Library of Medicine was conducted for articles published between January 1990 and January 2013 to identify literature presenting survival data on the topic of dental implants in patients receiving radiotherapy for head and neck cancer. Review and meta-analysis were performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses statement. For meta-analysis, only studies with a mean follow-up of at least 5 years were included.

Results

After screening 529 abstracts from the electronic database, we included 31 studies in qualitative and 8 in quantitative synthesis. The mean implant survival rate of all examined studies was 83 % (range, 34–100 %). Meta-analysis of the current literature (2007–2013) revealed no statistically significant difference in implant survival between non-irradiated native bone and irradiated native bone (odds ratio [OR], 1.44; confidence interval [CI], 0.67–3.1). In contrast, meta-analysis of the literature of the years 1990–2006 showed a significant difference in implant survival between non-irradiated and irradiated patients ([OR], 2.12; [CI], 1.69–2.65) with a higher implant survival in the non-irradiated bone. Meta-analysis of the implant survival regarding bone origin indicated a statistically significant higher implant survival in the irradiated native bone compared to the irradiated grafted bone ([OR], 1.82; [CI], 1.14–2.90).

Conclusions

Within the limits of this meta-analytic approach to the literature, this study describes for the first time a comparable implant survival in non-irradiated and irradiated native bone in the current literature. Grafted bone combined with radiotherapy was identified as a negative prognostic factor on implant survival.

Clinical relevance

The evolution of implant hardware and improvement of treatment strategies during the last years have affirmed dental implant-supported concepts as a valuable treatment option for patients with a history of radiation in the head and neck region.     

Kombination der Sinusliftoperation mit der lateralen Kieferkammaugmentation

Purpose

This paper describes a surgical and prosthetic procedure for treating the extremely atrophic maxilla. It explains a two-staged surgical technique, donor and recipient site morbidity, implant survival, and the implant-retained prosthetic rehabilitation of the patients.

Patients and methods

A total of 57 consecutive patients were treated with a sinus lifting procedure and a simultaneous lateral augmentation using autogenous corticocancellous block and particulate bone grafts from the iliac crest. After a 6-month bone healing period, a total of 284 endosteal Titanium screw implants were inserted. Following a 3-month osseointegration period, the implants were exposed and loaded with either fixed or removable prostheses.

Results

In three cases a partial bone graft loss was observed; however, enosseous implantation was possible as planned. During the observation period none of the 284 implants was lost; 3 implants exhibited treatable peri-implant infection. Complications at the donor and recipient sites were minimal and did not negatively influence the overall clinical result of the treatment.

Conclusion

The combination of sinus lift procedure and lateral augmentation for the treatment of the extremely atrophied maxilla proved to be a safe method that produces good and reliable clinical results.     

Maxillary zygomatic hexagonal implant system (MZH system) for severe resorption: a new technique

Introduction

The biomechanical demands of the severely resorbed maxilla have prompted the search for alternative points of anchorage for zygomatic implants that allows stabilizing a prosthesis in young patients (30 years old or more) for restitution of function and form. The purpose of this study is to describe the protocol of zygomatic hexagonal implants in patients with severe maxillary bone resorption.

Materials and methods

Ten patients with severe maxillary resorption were treated with hexagonal implants system, they were evaluated at the preoperative and the postoperative periods for a minimal of 24 months, and the evaluation was clinical and trough conventional radiographs and CT scans. Six implants according to prosthetic prior planning were placed in each patient. Anteroposterior severely resorbed maxilla was evidence. Patients were rehabilitated with immediate provisional prosthesis. Ten days after surgery, definitive prosthesis metal structures were designed and adapted.

Results

Force distribution and load concentration were balanced; adjustment of the metal bar was passive. Correction of skeletal relationship was evident. No fatigue in the later additions in controls was observable. No complications were found in the immediate postoperative period and late (6–24 months), no patients dropped out from the study, and all were followed up to 24 months.

Conclusions

The zygomatic hexagonal implants’ protocol guarantees barrier function, biomechanical stability, load distribution, and preventing fatigue bone/implant interface, which allows distributing of the forces through the pillars, anterior masticatory load reduction, and correcting the skeletal class III type which occurs in patients with severe resorption.

     

Efficacy of parathyroid hormone supplementation on the osseointegration of implants: a systematic review

Objective

The aim of the present systematic review was to assess the efficacy of parathyroid hormone supplementation on the osseointegration of implants.

Methods

The addressed focused question was Does parathyroid hormone supplementation affect osseointegration around implants? Indexed databases were searched from 1965 up to and including April 2015 using various key words including: Bone to implant contact; implant; parathyroid hormone; and osseointegration. Letters to the Editor, case-reports/case-series, historic reviews, commentaries and articles published in languages other than English were excluded. The pattern of the present systematic review was customized to primarily summarize the pertinent data.

Results

Eighteen studies fulfilled the eligibility criteria. Evidence was limited to preclinical animal studies only (11 studies in rodents, 4 in dogs and 3 in rabbits). Number of titanium implants placed ranged between 20 and 80 implants. Results from 16 studies showed that PTH supplementation enhanced new bone formation and/or BIC around implants. One study suggests that PTH-coated implants improve BIC and BA. One study showed no significant difference in BIC and new bone formation around implants with PTH hydrogel placement.

Conclusion

Efficacy of PTH supplementation on osseointegration of implants shows promising results in animal models, however further investigation is necessary to assess the effectiveness in humans.

     

Implants in the zygomatic bone for maxillary prosthetic rehabilitation: a systematic review

The purpose of this systematic review was to evaluate clinical studies on the follow-up survival of implants inserted in the zygomatic bone for maxillary rehabilitation. A comprehensive search of studies published from 2000 to July 2012 and listed in the PubMed/MEDLINE, Embase, and Cochrane Library databases was performed in accordance with the PRISMA statement. Relevant studies were selected according to predetermined inclusion and exclusion criteria. The initial database search yielded 751 titles. After filtering, 313 abstracts were selected, culminating in 42 full text articles. Application of eligibility criteria led to the elimination of 17 articles. Hence 25 full-text articles were considered clinically relevant and were included. Calculations of the interval survival rates and cumulative survival rates of implants could be carried out on the data extracted from the final list of included studies for the different time intervals. These studies reported the insertion of a total of 1541 zygomatic implants and 33 implant failures. Failure generally occurred during the first year interval and was related to clinical complications, such as recurrent acute and chronic sinusitis. After a 36-month follow-up, the survival rate was 97.86%. Additional studies with longer follow-up periods, including the number of zygomatic implants inserted and details of the variations in the surgical techniques used and the impact of the maxillary morphology are still required.     

Calvarial grafts for alveolar ridge reconstruction prior to dental implant placement: an update

Purpose

The aims of this review were to analyze publications related to alveolar crest reconstruction using calvarial grafts and to evaluate the survival and success rates of implants placed into the augmented area.

Methods

An automated search was made in MEDLINE of clinical publications from 2000 to 2013. Only publications with at least five patients and a minimum follow-up of 6 months were included.

Results

Graft success ranged between 97 and 100 %. Donor site complications were minimal. The most frequent complications in the recipient site were wound dehiscence. Prosthodontic loading time in most of the studies was 3 months. Implant survival rates ranged between 95 and 100 %. Implant success rates were between 90.3 and 95.05 %.

Conclusions

Grafting procedures with calvarial transplants show a high graft success rate and a sufficient implant success rate. Calvarial bone grafts are a reliable procedure for alveolar crest reconstruction.     

A systematic review of the clinical survival of zirconia implants

Objectives

The aim of this review was to evaluate the clinical success and survival rates of zirconia ceramic implants after at least 1 year of function and to assess if there is sufficient evidence to justify using them as alternatives to titanium implants.

Materials and methods

An electronic search in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Clinical Trials (CENTRAL) databases was performed in April 2015 by two independent examiners to retrieve clinical studies focusing on the survival rate of zirconia implants after at least 1 year of function. Implant survival was estimated using the overall proportion reported in the studies with a Clopper-Pearson 95 % confidence interval (random effect model with a Der-Simonian Laird estimate).

Results

Fourteen articles were selected out of the 1519 titles initially screened. The overall survival rate of zirconia one- and two-piece implants was calculated at 92 % (95 % CI 87–95) after 1 year of function. The survival of implants at 1 year for the selected studies revealed considerable heterogeneity.

Conclusions

In spite of the unavailability of sufficient long-term evidence to justify using zirconia oral implants, zirconia ceramics could potentially be the alternative to titanium for a non-metallic implant solution. However, further clinical studies are required to establish long-term results, and to determine the risk of technical and biological complications. Additional randomized controlled clinical trials examining two-piece zirconia implant systems are also required to assess their survival and success rates in comparison with titanium as well as one-piece zirconia implants.

Clinical relevance

Zirconia implants provide a potential alternative to titanium ones. However, clinicians must be aware of the lack of knowledge regarding long-term outcomes and specific reasons for failure.

     

Mesiodistal tooth size in non-syndromic unilateral cleft lip and palate patients: a meta-analysis

Objectives

To evaluate, using meta-analysis methodology, mesiodistal tooth dimensions in non-syndromic unilateral cleft lip and palate (CLP) patients.

Materials and methods

A literature search was conducted using PubMed, Medline, Google Scholar Beta, EMBASE Excerpta Medica, CINAHL, Web of Science, and the Cochrane Collaboration, identifying English and non-English articles reporting on mesiodistal tooth dimensions on the cleft and non-cleft side of non-syndromic unilateral CLP patients. Additional studies were identified by searching reference lists of articles consulted. Only studies with a suitable control group were included. Two examiners independently performed the literature search and data extraction. Using meta-analysis software, data extracted from each selected study were statistically combined using the fixed-effects model. Weighted mean differences, 95 % confidence intervals, and heterogeneity were calculated for each measurement.

Results

Four articles fulfilling the inclusion criteria were located and included in the meta-analysis. Maxillary incisors and first molars were found to be significantly larger on the non-cleft side while mandibular incisors and premolars were larger on the cleft side, in non-syndromic unilateral CLP patients. On the cleft side, maxillary premolars and second molars were larger in cleft than control patients while incisors were smaller, whereas all mandibular teeth were larger in cleft patients. On the non-cleft side, all maxillary teeth except for the central incisors were larger in the cleft than control patients, while all mandibular teeth were larger in the cleft patients except for lateral incisors.

Conclusions

Non-syndromic unilateral CLP patients tend to have larger posterior but smaller anterior teeth compared with the general population. Comparing sides, unilateral CLP patients tend to have smaller maxillary but larger mandibular teeth on the cleft than on the non-cleft side.

Clinical relevance

Given that obtaining a stable, functional, and esthetic occlusion requires a thorough evaluation of tooth size, knowledge about trends in tooth size variations in CLP patients can help with dental and orthodontic treatment planning.     

Resorbable Implants in Maxillofacial Surgery: A Reality Check

Background

Stability is the main feature of fixation techniques in fracture management modalities, in vogue today. One of the most significant landmarks in the armamentarium of maxillofacial fracture management has been the introduction of rigid internal fixation (RIF). The biomaterials used in RIF have seen a gradual change from Stainless steel to titanium due to the evidence based advantages of the latter. However, the inherent problems with metallic implants led to the introduction of resorbable polymers in RIF.

Materials and Method

This article evaluates the efficacy of these polymers in fixation of bone segments as compared to titanium fixation implants in 40 patients of zygomatic complex fractures. The study compared the clinical efficacy, technique, cost and time factors in the use of these two biomaterials.

Results

The results showed very little difference after the use of these two biomaterials in spite of the increased time, technique sensitivity and cost of the resorbable system.

Conclusion

The argument for use of the resorbable fixation implants as a better alternative to titanium in maxillofacial fracture management seems overstated considering the insignificant differences in the results obtained but significant differences in the time taken and economics of the two biomaterials. The resorbabale system should ideally be restricted for use in pediatric craniofacial surgery.     

Sinusbodenelevation und -augmentation

Aim

It was the aim of this investigation to analyze evidence of prognosis, predictors, and risk factors concerning sinus floor elevation and augmentation (SFEA).

Materials and methods

A MEDLINE search was performed to analyze the literature published between 1990 and 2002, limited to keywords (“sinus floor elevation and dental implants”, “complications”, “success”), study type (randomized as well as clinical prospective studies, retrospective studies, reviews), and language (German or English).

Results

Of 229 publications identified, 72 met the inclusion criteria (22 prospective and 47 retrospective studies, 3 reviews). Considering the augmentation material [autogenous bone (AB), bone substitution materials (BSM), and combinations of AB and BSM], the frequency of implant loss was not significantly different (AB 8%, BSM 9%, AB + BSM 5%, p>0.09) after an observation period of 2–4 years . The average duration of the healing period was 6 months (AB) and 8 months (BSM) with simultaneous SFEA and implantation and 6–7 months (AB and BSM) for the staged approach after an average healing period of 6 months for the augmentation materials. Frequency of implant loss was not different between simultaneous and staged approaches (7–8%). Postoperative sinusitis occurred in 3–8% of the cases. Smoking, positive sinusitis history, obstructive pathoses of the nose and ostium, allergic rhino-pathoses, use of short implants (<13 mm), treatment of edentulous maxilla compared to partially edentulous maxilla, bruxism, and uncontrolled early loading of implants were identified as predictors for complications.

Conclusions

Presupposing proper consideration of indications, SFEA should be considered as an evidence-based and clinically established method for implant prosthetic rehabilitation of the atrophic posterior maxilla with an overall cumulative survival rate of 90% within an average observation period of 4 years.     

Root resorption of endodontically treated teeth following orthodontic treatment: a meta-analysis

Objective

The aim of this meta-analysis was to investigate the effect of orthodontic treatment on root resorption of endodontically treated teeth compared to vital teeth.

Materials and methods

A literature search was conducted in 18 electronic databases. Review articles and relevant articles were searched for cross-references. Two independent reviewers screened all articles according to predefined inclusion and exclusion criteria and extracted the corresponding data. The pooled estimate of mean difference of root resorption weighted by the fixed-effect model and the corresponding 95 % confidence intervals (CIs) were used to construct a forest plot by implementing the “RevMan 5.1” software. Quality and heterogeneity assessments as well as publication bias evaluation and sensitivity analyses were performed. Inter-reviewer agreement for data selection, data extraction and quality analysis was evaluated by Cohen’s kappa.

Results

Six out of 1,942 original papers met the inclusion criteria. Four out of six studies were included in the quantitative analysis. Root resorption was less in endodontically treated teeth than in vital teeth (MD?=??0.48 mm; 95 % CI?=??0.81 to ?0.14 mm). The funnel plot indicated no evidence of publication bias, while no data heterogeneity was present (I ²?=?0 %). However, the overall quality of the included studies was considered as “low.”

Conclusions

Following orthodontic treatment, endodontically treated teeth exhibit relatively less root resorption than teeth with vital pulps.

Clinical relevance

Clinicians should consider orthodontic movement of endodontically treated teeth as a relatively safe clinical procedure.