Flap versus flapless procedure for ridge preservation in alveolar extraction sockets: a histological evaluation in a randomized clinical trial.

OBJECTIVE: The aim of this study was to evaluate and compare the histological and histomorphometric features of two different procedures carried out in extraction socket grafting; namely, the flapped and flapless technique. MATERIALS AND METHODS: Patients considered eligible for the study were randomized to receive tooth extraction and ridge preservation with the porcine bone and collagen membrane, with a full thickness mucoperiosteal flap and primary soft tissue closure (control group), or, with a flapless procedure and a secondary soft tissue closure (test group). After 3 months of healing, the surgical re-entry procedure was performed and implants were inserted in the test as well as in the control sites. Bone core samples were harvested from both groups and processed to be observed under light microscopy. Outcome variables were percentages of newly formed bone, residual graft particles and marrow spaces. RESULTS: Thirty-four patients were enrolled in the study. All of the scheduled implants were placed. Histological and histomorphometrical analyses did not report significant differences between the two groups (with P-values ranging from 0.690 to 0.917). The mean percentages of newly formed bone, soft tissues and residual grafted particles were 22.5 and 22.5%, 59.3 and 59.4%, and 18.6 and 18.2% respectively for flap and flapless approach. CONCLUSION: No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures.

Buccal bone deficiency in fresh extraction sockets: a prospective single cohort study.

OBJECTIVE: The purpose of this prospective single cohort study was to evaluate the use of xenograft and collagen membranes in treating full or partial buccal bone defects of fresh extraction sockets in the esthetic zone. MATERIALS AND METHODS: Thirty-three patients requiring tooth extraction in the anterior maxillary area and showing a complete or partial buccal bone plate deficiency (more than 2 mm) were consecutively enrolled and treated. Corticocancellous porcine bone and platelet-rich fibrin (PRF) with a collagen membrane were used to graft the extraction sockets, and the membranes were left exposed to the oral cavity with a secondary soft tissue healing. The outcome variables were as follows: width of keratinized mucosa, facial soft tissue levels, clinical bone changes (measured with a clinical splint), implant and prosthesis failures, and peri-implant marginal bone changes. RESULTS: All treated sites allowed the placement of implants; the width of keratinized mucosa at the mid-facial aspect showed an increase of 2.3 mm 5 months after the grafting procedure, and its value was 3.2 ± 0.6 mm at 1-year follow-up. The mean values of the facial soft tissue level indicated an increase over time. The bone level showed an improvement of 0.8 ± 0.1 mm and 0.7 ± 0.1 mm at mesial and distal sites, respectively, when compared to the baseline measurements. Finally, in the palatal area, no bone changes were observed. No implant failed during the entire observation period. CONCLUSIONS: Findings from this study showed that xenograft and PRF, used for ridge preservation of the extraction sockets with buccal bone plate dehiscence in the esthetic zone, can be considered effective in repairing bone defects before implant placement. The secondary soft tissue healing over the grafted sockets did not compromise bone formation; moreover, the soft tissue level and the width of keratinized gingiva showed a significant improvement over time.

The use of bone block allografts in sinus augmentation, followed by delayed implant placement: A case series.

PURPOSE: This article reports the clinical outcomes observed in a large number of patients receiving block bone allograft used for sinus augmentation and delayed implant placement. PATIENTS AND METHODS: In total, 28 patients (13 males) with a mean age of 49.8 ± 10.1 years (range: 33-67 years) were included in this case series. All selected patients suffered from severe alveolar ridge atrophy in the posterior maxilla and required bone augmentation procedures, followed by implant placement after 6 months. All patients were followed for 18 months after the grafting, with scheduled monthly visits and/or more frequent visits if required. The survival rates for both the bone blocks and placed implants were then evaluated. RESULTS: A total of 42 blocks and 90 implants were placed. Only one bone graft and 5 implants failed; the survival rate was 97.2% and 95.5% for the bone grafts and implants, respectively. The graft failed due to the onset of post-surgical infectious sinusitis, while in some patients' implants showed absence of osteointegration at the end of the healing phase. Of note, all failed implants were observed in heavy smokers; in all other patients, blocks and implants were successful. CONCLUSIONS: This preliminary case series suggests that the grafting of bone allograft followed by delayed implant placement may be a promising strategy for sinus augmentation. More extended and larger follow-up studies are needed to confirm this preliminary data.

An evaluation of new designs in implant-abutment connections: a finite element method assessment.

PURPOSE: This research sought first to evaluate the differences in the finite element method (FEM) analysis of 4 different implant surfaces, including internal and external connections of the same manufacturer with additional modifications. METHODS: In this study, 4 dental implants from the same manufacturer were compared. A connection system was modified with a collar to improve its stability. A nonlinear dynamic analysis by FEM was used to calculate the transient response of the dental implant systems. RESULTS: The results of FEM analysis indicated that the implant-modified configuration is more efficient in loading support when compared with the others. CONCLUSION: In the present research, 4 different types of connections were evaluated: a modified internal hex connection with a collar (to increase stability), an internal hex connection, a standard connection without hex, and an external connection. These data demonstrated that the internal hex connection with the modification of the manufacturer's original is much more resistant to loosening and/or distortion than the traditional hex.

Leader genes in osteogenesis: a theoretical study.

Little is still known about the molecular mechanisms involved in the process of osteogenesis. In this paper, the leader genes approach, a new bioinformatics method which has already been experimentally validated, is adopted in order to identify the genes involved in human osteogenesis. Interactions among genes are then calculated and genes are ranked according to their relative importance in this process. In total, 167 genes were identified as being involved in osteogenesis. Genes were divided into 4 groups, according to their main function in the osteogenic processes: skeletal development; cell adhesion and proliferation; ossification; and calcium ion binding. Seven genes were consistently identified as leader genes (i.e. the genes with the greatest importance in osteogenesis), while 14 were found to have slightly less importance (class B genes). It was interesting to notice that the larger part of leader and class B genes belonged to the cell adhesion and proliferation or to the ossification sub-groups. This finding suggested that these two particular sub-processes could play a more important role in osteogenesis. Moreover, among the 7 leader genes, it is interesting to notice that RUNX2, BMP2, SPARC, PTH play a direct role in bone formation, while the 3 other leader genes (VEGF, IL6, FGF2) seem to be more connected with an angiogenetic process. Twenty-nine genes have no known interactions (orphan genes). From these results, it may be possible to plan an ad hoc experimentation, for instance by microarray analyses, focused on leader, class B and orphan genes, with the aim to shed new light on the molecular mechanisms underlying osteogenesis.

Tissue changes of extraction sockets in humans: a comparison of spontaneous healing vs. ridge preservation with secondary soft tissue healing.

INTRODUCTION: As a consequence of extraction, the height of the buccal wall tends to decrease and results in the disappearance of bundle bone. To modify bone remodelling after extraction, various ridge preservation techniques have been proposed. The present research was drawn up with the following considerations in mind: to evaluate and to compare changes of hard and soft tissues in post-extraction sockets which received a ridge preservation procedure, with post-extraction sockets which had healed naturally. MATERIALS AND METHODS: Each patient was randomly allocated to a test or control group using a specific software package. After extraction, the sockets were carefully inspected and any granulation tissue was removed. The control sites received silk sutures to stabilize the clot without any grafting material. The test sites were grafted with corticocancellous porcine bone and a collagen membrane. All experimental sites had the membranes left exposed to the oral cavity with a secondary wound healing. The thickness of the buccal alveolar bone, if present, was carefully measured at the time of tooth extraction using a calliper at 1 mm from the edge of the wall. The following clinical parameters were evaluated at baseline and after 4 months at implant placement: vertical bone changes, horizontal bone changes and width of keratinized gingiva. The length, diameter and need for additional bone augmentation were assessed for both groups at the time of implant insertion. RESULTS: The control group showed vertical bone resorption of 1 ± 0.7 mm, 2.1 ± 0.6 mm, 1 ± 0.8 mm and 2 ± 0.73 mm at the mesial, vestibular, distal and lingual sites respectively. Moreover, changes in horizontal dimension showed an average resorption of 3.6 ± 0.72 mm. The test sites showed a horizontal bone remodelling of 0.3 ± 0.76 mm, 1.1 ± 0.96 mm, 0.3 ± 0.85 mm, 0.9 ± 0.98 mm at the mesial, vestibular, distal and lingual sites respectively. The horizontal bone resorption at the test sites was 1.6 ± 0.55 mm. The keratinized gingiva showed a coronal shift of 0.7 mm in the control group when compared to 1.1 mm in the test group. In addition, 42% of sites in the control group required an additional bone augmentation at implant placement, when compared to 7% in the test sites. CONCLUSIONS: This study clearly points out that an alveolar ridge preservation technique performed with collagenated porcine bone and a resorbable membrane--according to the procedure reported in this study--was able to limit the contour changes after tooth extraction. Finally, the test sites showed a better preservation of facial keratinized tissue when compared to control sites; grafted sites allowed the placement of longer and wider implants when compared to implants inserted in non-grafted sites.

Fracture of anterior iliac crest following bone graft harvest in an anorexic patient: case report and review of the literature.

In the treatment of jaw bone atrophies, autologus bone is still considered the gold standard because of its excellent osteoconductive, osteoinductive, and osteogenetic proprieties and lack of immunogenicity, which allow better graft integration and stability. Although various donor sites are available, the iliac crest represents the best source of corticocancellous bone, and literature suggests that it has low morbidity. However, this case report emphasizes that patients with systemic diseases such as anorexia should be carefully evaluated before such an operation, because unfavorable bone conditions may jeopardize the outcome. A 47-year-old woman needing rehabilitation of the upper arch was considered for iliac crest harvesting. She stated that she had suffered from anorexia for 30 years. A corticocancellous block was harvested by a bone saw using an anterolateral approach to the outer table of the right anterior iliac crest. The postoperative course was uneventful, but 13 days later, she complained of a sudden pain in the operated area, and X rays revealed a fracture of the anterior iliac crest. So far, the literature has mentioned 50 cases of iliac crest fractures after bone harvesting, and 28 cases among these are due to harvesting in the anterior part of the iliac crest. Several factors seem to be responsible for this complication, including the area of harvesting, residual bone thickness, technique used, and age and gender of the patient. To our knowledge, our case is the first of hip fracture after bone harvesting in a patient suffering from anorexia. Both low weight and osteoporosis are probably responsible for this complication. In our opinion, patients suffering from anorexia should be considered at risk for bone harvesting, and an appropriate mini-invasive surgical technique should be carried out instead.

Esthetic evaluation of single-tooth Morse taper connection implants placed in fresh extraction sockets or healed sites.

The aim of this study was to compare the esthetic outcome of single implants placed in fresh extraction sockets with those placed in fully healed sites of the anterior maxilla. This retrospective study was based on data from patients treated with single-tooth Morse taper connection implants placed in fresh extraction sockets and in fully healed sites of the anterior maxilla. Only single implant treatments were considered with both neighboring teeth present. Additional prerequisites for immediate implant treatment were intact socket walls and a thick gingival biotype. The esthetic outcome was objectively rated using the pink esthetic/white esthetic score (PES/WES). The Mann-Whitney U test was used to compare the PES and the WES between the 2 groups. Twenty-two patients received an immediate implant, and 18 patients had conventional implant surgery. The mean follow-up was 31.09 months (SD 5.57; range 24-46) and 34.44 months (SD 7.10; range 24-48) for immediately and conventionally inserted implants, respectively. No implants were lost. All implants fulfilled the success criteria. The mean PES/WES was 14.50 (SD 2.52; range 9-19) and 15.61 (SD 3.20; range 8-20) for immediately and conventionally placed implants, respectively. Immediate implants had a mean PES of 7.45 (SD 1.62; range 4-10) and a mean WES of 7.04 (SD 1.29; range 5-10). Conventional implants had a mean PES of 7.83 (SD 1.58; range 4-10) and a mean WES of 7.77 (SD 1.66; range 4-10). The difference between the 2 groups was not significant. Immediate and conventional single implant treatment yielded comparable esthetic outcomes.

An unusual case of unicystic intramural ameloblastoma and review of the literature.

Ameloblastoma is the most common tumor of odontogenic origin. There are various types of this tumor and confusion still exists among the clinicians about the correct classification. Multicystic ameloblastoma is the most frequent subtype while unicystic ameloblastoma can be considered as a variant of the solid or multycistic. This subtype is considered as a less aggressive tumor with a variable recurrence rate. However, its frequency is often underestimated. The aim of this article is reviewing the recent literature about unicystic ameloblastoma using our unusual clinical case as a starting point to illustrate this discussion. A 30-year-old man who had been complaining of slight pain in the premolar and molar area of the left side of mandible had a check up at our department. X-rays revealed a unilocular radiotrasparency with radiopaque margins. The first histological diagnosis was an odontogenic cyst. Successive histological evaluations revealed that ameloblastic epithelial islands were present in lassus connective tissue. We think that our case report provides new insights into the approach to the ameloblastoma diagnosis. We agree with authors who have pointed out that a single small biopsy may often be inadequate for the correct diagnosis of amelobastoma. Moreover, in the light of our experience, it should be kept in mind that ameloblastomas may have sometimes unusual presentations and this fact should induce surgeons and pathologists to consider carefully each lesion.

Immediate loading of mandibular overdentures supported by unsplinted direct laser metal-forming implants: results from a 1-year prospective study.

BACKGROUND: At present, only some studies have dealt with immediate loading of unsplinted implants supporting mandibular overdentures. The aim of this prospective study is to evaluate treatment outcomes of mandibular overdentures supported by four one-piece, unsplinted, immediately loaded, direct laser metal-forming (DLMF) implants by assessing implant survival rate, implant success, marginal bone loss, and prosthetic complications. METHODS: A total of 96 one-piece DLMF implants were inserted in the edentulous mandible of 24 patients. Four implants were placed in each edentulous mandible. Immediately after implant placement, a mandibular overdenture was connected to the implants. At 1-year follow-up, clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, suppuration, and implant mobility; absence of continuous peri-implant radiolucency; and distance between the implant shoulder and the first visible bone contact <1.5 mm. RESULTS: After a 1-year loading time, the overall implant survival rate was 98.9%, with only one implant lost. Among the surviving 95 implants, two did not fulfill the success criteria; therefore, the implant success rate was 97.8%. The mean distance between the implant shoulder and the first visible bone contact was 0.28 ± 0.30 mm (95% confidence interval, 0.24 to 0.32). Some prosthetic complications were reported. CONCLUSION: Based on the present results and within the limits of this study, the immediate loading of four unsplinted DLMF implants by means of ball attachment-supported mandibular overdentures seems to represent a safe and successful procedure.

Maxillary sinus augmentation using prehydrated corticocancellous porcine bone: hystomorphometric evaluation after 6 months.

BACKGROUND: Insufficient alveolar bone height often prevents the placement of standard dental implants in the posterior part of edentulous maxilla. In order to increase adequately the vertical dimension of the reabsorbed alveolar process, a sinus lift procedure is often necessary. The aim of this study was to evaluate histologic results of a prehydrated corticocancellous porcine bone used in maxillary sinus augmentation. METHODS: Patients (age 18-70 years) with a residual bone height requiring a maxillary sinus augmentation procedure to place dental implants were eligible for this study. All patients were treated with the same surgical technique consisting of sinus floor augmentation via a lateral approach. The space obtained by elevation of the mucosa wall was grafted with prehydrated and collagenated corticocancellous porcine bone. Biopsies were harvested 6 months after the augmentation procedures. RESULTS: Twenty-four patients were enrolled. The mean percentage of new formed bone was 43.9 ± 18.6% (range 7.5-100%), whereas the mean percentage of residual graft material was 14.2 ± 13.6% (range 0-41.9%). The new bone/residual graft material ratio in the maxillary sinuses was 3.1. The mean soft tissues percentage was 41.8 ± 22.7% (range 0-92.5%). CONCLUSION: The present study suggested that porcine bone showed excellent osteoconductive properties and could be used successfully for sinus augmentation. Moreover, the porcine bone showed a high percentage of reabsorption after 6 months; this might be because of the presence of collagen and the porosity of the graft material.

Single-tooth Morse taper connection implants placed in fresh extraction sockets of the anterior maxilla: an aesthetic evaluation.

OBJECTIVE: The aim of this retrospective study was to evaluate the aesthetic outcome of single-tooth Morse taper connection implants placed in fresh extraction sockets of the anterior maxilla, by means of the pink aesthetic/white aesthetic score (PES/WES) index. MATERIALS AND METHODS: Twenty-six adult patients (18 men, 8 women, aged between 20 and 62 years; average: 48.7 years) who were treated with an immediate, single-tooth Morse taper connection implant (Leone Implant System(R) , Florence, Italy) in the aesthetic area of the anterior maxilla, were enrolled in this retrospective study. An independent calibrated examiner applied the PES/WES index to 26 single-tooth implant-supported restorations, respectively, 3 months and 2 years after implant placement. RESULTS: No implants were lost. All 26 anterior maxillary single-tooth implants fulfilled the established success criteria for dental implants with regard to osseointegration, including the absence of pain, suppuration, clinically detectable implant mobility, peri-implant radiolucency and prosthetic complications at the implant-abutment interface, with an overall implant-crown success of 100.0%. At the 2-year examination, the mean DIB was 0.44 ± 0.14 mm (95% CI: 0.41-0.47); the mean total PES/WES was 14.30 ± 2.78 (range 8-19); the mean PES was 7.30 ± 1.78 (range 4-10) and the mean WES was 7.00 ± 1.35 (range 4-10). CONCLUSIONS: The immediate placement of single-tooth Morse taper connection implants in the anterior maxilla seems to represent a successful procedure, from an aesthetic point of view. Further studies are needed to evaluate the aesthetic outcome of single-tooth Morse taper connection implants placed in fresh extraction sockets of the anterior maxilla.

Morbidity associated with iliac crest harvesting in the treatment of maxillary and mandibular atrophies: a 10-year analysis.

PURPOSE: The iliac crest provides an important donor site for cancellous, cortical, and corticocancellous bone because it has the highest concentration of osteocompetent cells, offers sufficient volume, and is readily accessible. Although iliac crest harvesting is considered a common procedure in different medical specialities, donor site morbidity is a subject that requires further discussion. Moreover, the increasing number of bone grafts being undertaken stresses the importance of donor site morbidity in surgical planning and for patient consent. This study evaluated morbidity associated with iliac crest harvesting over a 10-year period and patients' overall satisfaction. MATERIALS AND METHODS: This prospective study involved 235 patients who were scheduled for iliac harvesting procedures from April 2001 through May 2010. A standardized surgical procedure with an anterior approach was used for the harvesting of all iliac crest grafts. The following variables were considered: pain, discomfort, presence of functional disorders, presence of sensory disturbances, esthetic outcome, and patients' general satisfaction, which were evaluated using specific tests or questionnaires. RESULTS: Ninety-nine percent of patients complained of mild pain 1 week after intervention but the pain rapidly disappeared after a few weeks. Functional disorders such as alterations in walking and lifting strength were reported by 100% of patients after intervention, but after 5 weeks this percentage had decreased substantially. Sensory disturbances such as hypoesthesia were recognized as transitory complications of iliac crest harvesting. A large percentage of patients were satisfied with the esthetic outcome of the intervention. CONCLUSIONS: Although the anterior iliac crest is a donor site with low morbidity, many studies have reported contrasting results. These data support the idea that the surgical approach plays a crucial role in decreasing postoperative morbidity. Moreover, this study confirmed that the anterior iliac crest can be considered a first-rate option for bone-defect reconstruction because of its low morbidity. However, future improvements in bone substitutes may well change this situation.

Morse taper connection implants supporting "planned" maxillary and mandibular bar-retained overdentures: a 5-year prospective multicenter study.

OBJECTIVES: In contrast to the excellent long-term outcomes described for implant-supported mandibular overdentures, less favorable long-term survival and success rates have been reported for maxillary implants supporting overdentures. The aim of this study was to evaluate the treatment outcome of "planned" bar-retained maxillary and mandibular overdentures supported by Morse taper connection implants, investigating implant survival, peri-implant tissue health, marginal bone resorption and prosthetic complications. MATERIAL AND METHODS: Over a 2-year period, 60 patients were enrolled in this study, in four different clinical centers. The overdentures (maxilla 38, mandible 34) were planned with support from four implants anchored on a bar. A total of 288 Morse taper connection implants (Leone Implant System(®)) were inserted (152 maxilla, 136 mandible). Implants were evaluated 5 years after insertion. Success criteria included the absence of pain, suppuration or clinical mobility, the distance between implant shoulder and first crestal bone-implant contact (DIB) <2 mm and no exudate history. RESULTS: The overall 5-year implant survival rate was 98% (maxilla 97.4%, mandible 98.6%), with 282 implants still in function. Among these surviving implants, 278 (98.6%) were classified in the success group. At the 5-year examination, the mean DIB was 0.7 mm (±0.53). Few prosthetic complications were reported. CONCLUSIONS: With "planned" bar-retained maxillary and mandibular overdentures supported by Morse taper connection implants, satisfactory survival and success rate can be achieved.