Oral rehabilitation with unilateral zygomatic implants: A case series of 32 patients.

AIMS: Zygomatic implants are successful alternatives to conventional dental implants for oral rehabilitation of patients with severely atrophic maxillae; however, the use of unilateral zygomatic implants needs to be studied further to validate their efficacy. The present investigation aimed to evaluate unilateral zygomatic implant placement in the oral rehabilitation of partially edentulous patients with extremely atrophic maxillary bone and/or previous implant failures. MATERIALS AND METHODS: This retrospective clinical study included patients with partially edentulous maxillae who underwent unilateral zygomatic implant insertion. The primary outcome was implant survival. Intraoperative, postoperative and prosthetic complications were also assessed based on patients' clinical records. RESULTS: A total of 32 patients (34 zygomatic implants) with a mean age of 60.45 ± 8.74 years (range 47 to 78 years) were included in the study. The mean follow-up period was 34.3 ± 25.5 months, and the overall implant survival rate was 100%. No intraoperative or postoperative complications developed in any of the patients, and no prosthesis failures or complications were recorded. CONCLUSIONS: The results indicate that unilateral zygomatic implant insertion for oral rehabilitation of patients with partially edentulous posterior maxillae with severely atrophic bone and/or previous implant failures can be considered a successful alternative to use of conventional dental implants associated with advanced bone grafting procedures.

Finding Better Ways to Perform Graftless Full Rehabilitation of a Compromised Maxilla: New Platform-Switched Zygomatic Implants Placed Extra-Sinus Improve Prosthetic Restoration-A Preliminary Study of 25 Cases and 85 Implants.

Standard treatment for full rehabilitation of compromised maxillae with regular implants includes sinus elevation grafting, a minimum of two to three surgeries, and a minimum treatment time of 9 to 15 months. Zygomatic implants are a viable alternative. However, prosthetic restorations have been compromised due to abutments emerging on the palate. The purpose of this study was to find ways that abutments will emerge on the ridge (occlusal surface). The presented results show it can be done if zygomatic implants are placed in the sinus wall (extra-sinus) and use an internal, conical connection with platform-switching and 45-degree abutments. Thus, marginal tissue prognosis and primary stability may also be improved by adding coronal threads to an implant design. These improvements, if confirmed in longer follow-ups and further studies, may encourage more graftless rehabilitations of severely compromised maxillae, reducing the number of surgeries and overall treatment time.

Analysis of IL-1ß, CXCL8, and TNF-α levels in the crevicular fluid of patients with periodontitis or healthy implants.

BACKGROUND: Our study aimed to assess the level of IL-1ß, CXCL8, and TNF-α in peri-implant sulcular fluid (PISF) collected from patients with no clinical symptoms of mucositis or peri-implantitis and compare them with cytokine concentration in gingival crevicular fluid (GCF) acquired from patients with healthy periodontium and those with varying severity of periodontitis. METHODS: A total of 189 subjects were included in the study, and GCF/PISF samples were checked for IL-1ß, CXCL8, and TNF-α levels using an ELISA test. RESULTS: The IL-1ß level in PISF in patients with implants was significantly lower than in GCF in patients with mild, moderate, or severe periodontitis. The CXCL8 level in PISF was considerably lower than in patients with moderate periodontitis. The TNF-α level in PISF in patients with implants was markedly higher compared to subjects with healthy periodontium or patients with mild periodontitis. CONCLUSION: Analysis of cytokine levels may help describe the pathogenesis and early diagnosis of peri-implantitis and prevision in high-risk patients.

A Possible Relationship between Peri-Implantitis, Titanium Hypersensitivity, and External Tooth Resorption: Metal-Free Alternative to Titanium Implants.

Titanium dental implant surface does not remain unaltered but may corrode and release ions or particles which trigger soft and hard tissue damage. Titanium may induce clinically relevant hypersensitivity in patients chronically exposed. A 56-year-old female patient presented peri-implantitis around a single titanium implant positioned three years earlier. Despite nonsurgical therapy, a rapid bone loss associated with pain and swelling occurred, and adjacent teeth presented external resorption. Compromised teeth were removed, and three titanium implants were inserted. Six months later, the patient complained about high mucosa sensitivity and implant exposure. At clinical and radiographic examinations, tissue inflammation and vertical bone loss involved the new implants and the process of external resorption affected the teeth. The blood test confirmed titanium hypersensitivity. Titanium implants were removed, and 5 zirconia implants were placed. No sign of bone loss or tooth resorption was recorded at clinical and radiographic control during 18 months of follow-up.

A Clinical and Radiographic Evaluation of Zirconia Dental Implants: 10-Year Follow-Up.

PURPOSE: The aim is to evaluate the survival and success rates, as well as the marginal bone loss (MBL) and periodontal indexes, of zirconia implants with 10-year follow-up. MATERIALS AND METHODS: 10 patients were selected and 26 one-piece zirconia implants were used for the rehabilitation of single tooth or partially edentulous ridge. After 10 years, a clinical-radiographic evaluation was performed in order to estimate peri-implant tissue health and marginal bone loss. RESULTS: The survival and success rates were 100%. The average marginal bone loss from baseline to 120 months after surgery was 0.92 ± 0.97 mm. CONCLUSION: One-piece zirconia dental implants are characterised by high biocompatibility, low plaque adhesion, and absence of microgap that can be related to the clinical success of these implants.

Extrasinus Zygomatic Implants for the Immediate Rehabilitation of the Atrophic Maxilla: 1-Year Postloading Results From a Multicenter Prospective Cohort Study.

PURPOSE: The use of zygomatic implants is an alternative to major grafting procedures for the treatment of the atrophic posterior maxilla. However, only few studies reported solid and correct data about the use of extrasinus zygomatic implants. Starting from these considerations, this study aims to investigate the 1-year survival and success rates of extrasinus zygomatic implants immediately loaded in patients with severe atrophy of the posterior maxilla. METHODS: Twenty-three consecutive patients fully edentoulus or with failing dentition in the upper arch and with a severe atrophy of the posterior maxilla were enrolled. All patients underwent prosthodontic rehabilitation with the application of implants in both anterior maxilla areas and zygomatic bone. All the zygomatic implants were inserted with an extrasinus path. Primary outcomes were prosthesis and implant failures. Secondary outcomes were complications, bleeding scores, probing pocket depths, and peri-implant marginal bone-level changes. A total of 98 implants were inserted. RESULTS: During the 1-year follow-up, no implant failure was reported as well as no pain and/or no sinusitis were detected. No other significant events were reported, except for minor soft tissue and technical problems. A maxillary sinus membrane rupture occurred during the surgical phase in 4 (17.4%) patients, but healing was not compromised. Peri-implant mucositis was observed in 2 (8.7%) patients. Twelve months after surgery, average bone loss around conventional implants was 1.11 ± 0.23 mm. In addition, no peri-implant radiolucency was observed around zygomatic implants. Within the limits of this study, preliminary short-term data (1-year after loading) suggested that extrasinus zygomatic implants represent a predictable treatment option for the atrophic maxilla. Further follow-up data (≥5 years) are needed to confirm these results. CONCLUSIONS: The present study supports the conclusion that extrasinus zygomatic implants for the immediate rehabilitation of the atrophic maxilla have high success rate with minimal or no complications.

Trefoil System for the Treatment of Mandibular Edentulism: A Case Report with 30 Months Follow-Up.

The purpose of this work is to describe a clinical case of full-arch mandible rehabilitation with a fixed prosthesis on three implants. The chosen protocol is the Trefoil system by Nobel (Nobel Biocare, Zurich, Switzerland) that allows to realize a mandibular fixed rehabilitation on three particularly designed fixtures through the use of prefabricated surgical guides and a preassembled bar on which the prosthesis is built. Both surgical and prosthetic procedures were completed without complications, and after 30 months, the rehabilitations are in good health conditions. The patient is able to maintain a good level of hygiene and is satisfied with the work from an aesthetic and functional point of view.

Classification of Sinus Membrane Perforations Occurring During Transcrestal Sinus Floor Elevation and Related Treatment.

The predictability of transcrestal sinus floor elevation (tSFE) in elevating the sinus membrane following posterior maxillary ridge resorption has been widely demonstrated. To minimize complications and increase success, a literature search was conducted to validate procedures used for tSFE. A decision tree based upon timing of perforations was then developed to improve membrane-perforation management during the procedure. At each surgical procedure, the clinician is encouraged to use size of the perforation, time during the procedure in which the perforation occurred, and resulting symptoms to determine the best treatment approach. This article discusses all possible sinus membrane perforations based on timing of that surgical procedure, allowing the clinician to recognize and successfully rectify this clinical complication while successfully completing the surgery. With this aim, a classification of sinus membrane perforations occurring during tSFE is proposed, simultaneously providing guidelines to effectively manage these complications.

Analysis of Forces Applied During Transalveolar Sinus Lift: A Preliminary Clinical Study.

PURPOSE: To introduce a novel modality that enables the measurement of forces applied during a transalveolar sinus floor elevation (tSFE) and to investigate the influence of anatomical and surgical factors on the necessitated force in sinus membrane detachment. MATERIAL AND METHODS: A new endosinus probe, innovated with a calibrated load cell, was used to test the forces needed to perforate ten maxillary sinuses in 5 human cadavers. The same probe was also used to detach the Schneiderian membrane from the bony floor of 21 human subjects undergoing tSFE. RESULTS: The force needed to cause membrane perforation in the cadaver sample was on average 3.46 ± 1.04 N. The maximum force applied in vivo to a sinus membrane without perforation was 2.01 ± 0.67 N on average. Regression analysis showed that smoking (P < 0.001), as well as 3.0 mm osteotomy (P < 0.001), was significantly correlated to increased forces during membrane detachment. CONCLUSIONS: The maximum force needed to detach the membrane was found to be, on average, lower than the membrane breaking load in cadavers. Furthermore, because of smoking and a 3.0-mm osteotomy diameter demonstrating a high association with increased forces during membrane detachment, they may be considered as risk factors of membrane perforation.

Sinus presurgical evaluation: a literature review and a new classification proposal.

INTRODUCTION: Presurgical evaluation with cone beam computed tomography (CBCT) or computed tomography (CT) has become an essential tool for diagnosis and surgical planning, including maxillary sinus floor elevation. Before performing a sinus lift, the clinician's attention should not be only directed to the patency of the ostium through CBCT or CT, because many anatomical features could influence the surgical approach of sinus floor elevation. The goal of this article was to facilitate the communication between clinicians regarding the type of maxillary sinus, encourage in-depth analysis prior to surgery and reduce the risk of complications due to possible underestimation of important parameters. EVIDENCE ACQUISITION: An electronic search was conducted in Pubmed, Embase, Medline and Scopus, matching the following keywords: "sinus lift", "CBCT", "CT", "presurgical" and "evaluation". Clinical Oral Implant Research, Implant Dentistry, International Journal of Periodontics and Restorative Dentistry and Journal of Oral Implantology were hand-searched. The bibliographies of review articles were checked and personal references were also searched. EVIDENCE SYNTHESIS: Eleven parameters, that clinicians must check every time through CBCT or CT, were evaluated from different studies. At the end of the literature review for every single feature, the Authors established a favorable, a normal and an unfavorable situation, in order to provide a new classification. CONCLUSIONS: The grade of the described classification may be useful for clinicians to understand what probably the risk level of the sinus lift surgery could be and it may encourage the surgeon to have a careful pre-operative evaluation through CBCT or CT.

Incidence and characteristics of mandibular accessory canals: A radiographic investigation.

AIM: The aim of the present study was to explore, through tridimensional reconstructions of cone-beam computed tomography (CBCT) scans, the presence and the characteristics of mandibular accessory canals. METHODS: For each included participant, the presence of accessory canals was recorded. The diameter of the canal, as well as the distance between the canal walls and the walls of the mandibular bone (lingual, buccal, cranial and caudal), were measured and recorded. RESULTS: Mandibular accessory canals could be found in 8.8% of participants. Retromolar canals were the most frequently found accessory mandibular canals. CONCLUSIONS: Accessory mandibular canals were found in a relatively high number of participants through the examination of CBCT scans and tridimensional reconstruction. The presence of such structures should be considered cautiously when planning and performing surgical interventions in mandibular area.

Microbiological analysis of bacterial plaque on three different threads in oral surgery.

BACKGROUND: Suture is the final act of most oral surgery procedures. The quality of healing after the operation depends on its efficiency. Sutures must not cause inflammation - neither directly nor indirectly. The objective of this study is to compare the bacterial colonization on different suture materials after a third molar extraction. METHODS: Thirty patients were randomly selected among people going under third molar extraction; they were divided into 3 groups and one suture type was used on each group. After 7 days distal stitches were removed by a single operator, placed in physiologic solution and analyzed after 2 or 3 hours. Patients followed the same postsurgical protocols; materials used were: Ethicon Silk® 4/0, B. Braun Dafilon® 4/0, and B. Braun Safil® 4/0. RESULTS: The amount of cocci and bacilli on the sutures analyzed shows that silk (Ethicon Silk) is the higher level of retention material where monofilament (B. Braun Dafilon) is the lower. There is a difference between monofilament and polyglycolide (B. Braun Safil), as the former is less retentive than the latter, although not significantly so. CONCLUSIONS: A less plaque retention, and consequently a fewer bacterial presence, is crucial to minimize the inflammatory process and allow a better tissue healing. Since the capability of brushing and, of course, the final personal hygiene depends on multiple variables, we must use surgical protocols able to minimize the effect of improper cleaning on the healing process: this statement implies the use of low plaque retention materials. The use of monofilament or polyglycolide threads in sutures can help reducing bacterial concentration and therefore promotes a faster and better healing.

CBCT evaluation of the tridimensional relationship between impacted lower third molar and the inferior alveolar nerve position.

BACKGROUND: The aim of this study is to evaluate if the statistical significant relations between the measures taken exists or not and to show how the 3D reconstruction could be help the oral surgeon in all those instances in which it may have a direct impact on the planning of the surgical steps. METHODS: Thanks to use of NobelClinician™ Software it was possible to analyze 200 mandibular tomography computerized, random selected, and create a 3D reconstruction of mandibular bone, point out dental structure of wisdom tooth and the way of IAN. Statistical analysis was performed using the Statistical Package for Social Sciences. One way ANOVA test was used to measure the association between each independent variable and the outcome variable, followed by the post-hoc least significant difference (LSD) test for intergroup differences. RESULTS: Two independent variables were significant predictors for risk to have the distance 0 mm from IAN to apex: "Ramus relationship/space available" and "depth". CONCLUSIONS: The 3D reconstruction software provide surgeons with an additional planning tool, offering: immediate and neat visualization of the noble structures that have to be respected and their localization in the three spatial planes; the exact morphology of the relevant root apex; a 360° view of the relationship between the IAN and the third molar and the exact point in which the root is in relationship with the canal.

Infection Related Inferior Alveolar Nerve Paresthesia in the Lower Premolar Teeth.

Introduction. The aim of this paper was to describe two cases of IAN infection-induced paresthesia and to discuss the most appropriate treatment solutions. Methods. For two patients, periapical lesions that induced IAN paresthesia were revealed. In the first case, the tooth was previously endodontically treated, whereas in the second case the lesion was due to pulp necrosis. Results. For the first patient, a progressive healing was observed only after the tooth extraction. In the second patient, the paresthesia had resolved after endodontic treatment. Conclusions. The endodontic-related paresthesia is a rare complication that can be the result of a combination of etiopathogenic mechanisms such as mechanical pressure on the nerve fibers due to the expanding infectious process and the production of microbial toxins. Paresthesia resulting from periapical lesions usually subsides through elimination of infection by root canal treatment. However, if there are no signs of enhancement, the immediate extraction of the tooth is the treatment of choice in order to prevent irreversible paresthesia because it was demonstrated that there is a correlation between the duration of mechanical or chemical irritation and the risk of permanent paresthesia.

Long-Term Retrospective Evaluation of Dental Implants Placed in Resorbed Jaws Reconstructed With Appositional Fresh-Frozen Bone Allografts.

INTRODUCTION: The aim of this study was to evaluate the outcome of fresh-frozen bone allografts in preprosthetic surgery for implant placement purposes. MATERIALS AND METHODS: The cohort comprised 45 patients treated with fresh-frozen bone block grafts and dental implants. Clinical and radiological evaluations were performed to evaluate the survival rate. The data were statistically analyzed with the Kaplan-Meier estimator to assess the influence of possible predictors of implant failure on survival. RESULTS: Overall, 262 implants were retrospectively analyzed. The survival rate was 90.84% over a mean follow-up of 50 months. Comparing the donor site and the position of the implants, no statistically significant differences could be detected (P = 0.7194 and P = 0.2901, respectively), whereas sex resulted in a marginally statistically significant difference (P = 0.0581). When considering age categorized on the median value (≤55/>55 years), age resulted in a statistically significant difference (P = 0.0340), with higher failures found in older people. CONCLUSION: Implant loss was strictly related to the lack of primary osseointegration. Female sex and old age were found to be risk factors, which could negatively influence implant survival.

Crestal sinus lift by using a mini-invasive procedure: a case series.

BACKGROUND: The aim of this study was to present a case series treated with an atraumatic procedure for maxillary sinus lift by crestal approach. This technique avoids the use of classical osteotomes, thus decreasing complications due to percussive and vibratory forces. METHODS: Three cases of partial edentulism in the distal maxillae with inadequate bone volume are treated by using SinCrest procedure (Meta, Reggio Emilia, Italy). With the guide of surgical templates, the sinus lift was performed, and implants were placed during the same procedure. After 6 months an X-ray was taken to check the success of the operation. RESULTS: SinCrest allows the operator to advance progressively, maintaining the correct axis for implant placement. The plane tip of drills prevents accidental perforations of Schneiderian mucose, and the stops, available in different lengths, avoid the overtreatment. The manual screwing of SinCrest osteotome ensures precision during the cortical approach, while the built-in probe allows to check residual strength of sinusal floor, making sure that the Schneiderian mucose is reached and lifted. This technique does not depend on the operator's skills and decreases the onset of adverse effects due to the hammering with classical osteotomes. SinCrest requires a small flap and osteotomy, which means less healing time and more comfort for the patient, both during and after the surgery. CONCLUSIONS: SinCrest is a valid alternative to other mini-invasive procedures for sinus lift in cases with a residual height bone of at least 5 mm, allowing an atraumatic, safe and controlled operation.

Zirconia Implants in Esthetic Areas: 4-Year Follow-Up Evaluation Study.

Objectives. The aim is to evaluate the survival and success rates, as well as the marginal bone loss (MBL) and periodontal indexes of zirconia implants positioned in the esthetic jaw areas. Materials and Method. 13 patients were selected and 20 one-piece zirconia implants were used for the rehabilitation of single tooth or partially edentulous ridge in the esthetic jaw areas. Six months after surgery and then once a year, a clinical-radiographic evaluation was performed in order to estimate peri-implant tissue health and marginal bone loss. Results. The survival and success rates were 100%. The average marginal bone loss from baseline to 48 months after surgery was +2.1 mm. Four years after surgery, the median and the mode for visible Plaque Index and Bleeding On Probing resulted 1 whereas Probing Pocket Depth amounted to 3 mm (SD = ±0.49 mm). Conclusion. One-piece zirconia dental implants are characterized by high biocompatibility, low plaque adhesion, and absence of microgap that can be related to the clinical success of these implants even in the esthetic areas.

Poly-D-L-Lactic Acid Membranes for Bone Regeneration.

PURPOSE: To histologically and histomorphometrically evaluate the biocompatibility and the biological properties of perforated and nonperforated poly-D-L-lactic acid (PDLLA) resorbable membranes, using a model of calvarial monocortical bone defects in domestic pigs. METHODS: A total of 6 10 × 10 × 10  mm circular calvarial bone defects were prepared in each of the 3 adult female large white domestic pigs and assigned to the following experimental groups: negative control, nonperforated membrane only, perforated membrane only, bone only, bone + nonperforated membrane, and bone + perforated membrane. The PDLLA membranes were fixed by PDLLA pins by means of an ultrasonic device. After 40 days, bone blocks containing the defects were harvested and histologically processed. RESULTS: A close contact between the PDLLA devices and the surrounding bone was found, and no trace of inflammatory tissue or signs of infection were detected. Bone regeneration occurred from the preexisting bone with a centripetal pattern. Incomplete bone filling was found in empty defects, whereas all sites filled with bone showed a complete bone formation, irrespectively of the presence and the type of membrane used. CONCLUSION: PDLLA membranes and pins showed to be highly biocompatible toward bone tissue and to do not interfere with the bone healing process of monocortical calvaria defects in domestic pigs. No adjunctive effect of PDLLA membranes, irrespectively of their perforated/nonperforated structure, could be evidenced in terms of bone regeneration under the present experimental conditions. Further studies are needed to investigate the regenerative potential of such devices in other clinically relevant models.

Maxillary Sinus Septa and Anatomic Correlation With the Schneiderian Membrane.

Aim of this investigation is to evaluate prevalence, localization, and height of 114 maxillary sinus septa by using cone-beam computed tomography scans. The thickness of the mucosa has been measured together with the variations of the membrane in relation to those septa. A total of 228 maxillary sinuses have been considered. Septa were identified using "panorex" reconstructions and axial scans of cone-beam computed tomography using the software "eXamVision." The thickness of the mucosa has been evaluated in the paraxial scans and related to those septa where they were present. In the current study, the prevalence of sinus septa is 38.1%. Significant difference can be found in the height of primary and secondary septa. The mean height of primary septa was 5.5 mm (± 1.19) and of secondary septa 3.4 mm (± 1.6). Anterior and medium septa resulted significantly higher than posterior septa (P = 0.003). The medium thickness of the mucosa was 0.85 mm (± 0.58), whereas close to the septa it turned out to be 1.8 mm (± 1.87). The difference is statistically relevant (P = 0.003). There is no statistically significant proportional relation between dimensions of septa and thickness of mucosa (P = 0.53). Underwood septa are frequent anatomic variations of the maxillary sinus. Their presence may result in a thickening of the sinus membrane. The systematic study of radiographic anatomy of maxillary sinus is necessary before the sinus lift surgery planning.

Odontogenic keratocyst mimicking paradental cyst.

Objective. The aim of this paper is to present an uncommon clinical and radiographic aspect of odontogenic keratocyst (OKC) mimicking paradental cyst. Methods. A 32-year-old female patient showed a well-delimited radiolucent lesion connected with the root of the left third molar with close anatomical relationship with the mandibular canal. The clinical, radiographic, and anamnestic features lead us to diagnose a paradental cyst that was treated by enucleation after extraction of the partially impacted tooth. Results. Histological analysis showed typical histological features of PKC such as the presence of a lining of stratified squamous epithelium with a well-defined basal layer of palisading columnar of cuboidal cells. Conclusion. Initial X-ray analysis and the position of the lesion related to the third mandibular tooth caused us to mistakenly diagnose a paradental cyst. We were only able to identify the cyst as an PKC rather than a paradental cyst after histological analysis.