The effect of a flapless alveolar ridge preservation procedure with or without a xenograft on buccal bone crest remodeling compared by histomorphometric and microcomputed tomographic analysis

Evaluation of photodynamic therapy efficacy vs. conventional antifungal therapy in patients with poor-fitting dentures suffering from denture stomatitis. A prospective clinical study

BACKGROUND

The long-term use of antifungal therapy in denture stomatitis (DS) treatment could be accompanied by antifungal-resistant strain onset, leading to compromised therapeutic procedure and disease reappearance. Photodynamic therapy (PDT) has shown the ability to eradicate oral infections and resistance strains. This prospective clinical study aimed to assess the PDT's effectiveness compared to the conventional treatment on clinical and microbiological parameters in patients with DS without denture wear during the treatment and follow-ups.

METHODS

Forty-two patients diagnosed with DS were randomly assigned to one-session single PDT application (test group) or conventional antifungal therapy (control group). Clinical and microbiological parameters were assessed and analyzed before and at 3rd, 15th, and 30th day following the treatments. Microbiological samples were analyzed by a Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The data was statistically analyzed.

RESULTS

Prior to the treatment, Candida species, including C. albicans (100%), C. glabrata (33%), C. tropicalis (31%), C. krusei (31%) were isolated in all patients. Both treatment procedures demonstrated a statistically significant reduction in C. albicans at all follow-up time intervals (p < 0.05). However, PDT displayed a statistically significant reduction in C. krusei compared to the conventional treatment at all follow-up periods (p < 0.05). Clinical parameters improved considerably in the test group compared to the control group at the 3rd and 15th day of follow-up.

CONCLUSION

One-session single PDT application demonstrated significant improvement in both clinical and microbiological outcomes in a short-term period, resulting in complete Candida spp. eradication compared to conventional antifungal therapy.

Alveolar Bone Remodeling with or without Collagen Filling of the Extraction Socket: A High-Resolution X-ray Tomography Animal Study

The healing process of the tooth extraction socket often leads to significant resorption of the alveolar bone, eventually causing clinical difficulties for future implant-supported rehabilitations. The aim of the present animal study was to evaluate alveolar bone remodeling after tooth extraction in a rabbit model, either with or without the use of a plain collagen plug inside the socket, by means of micro-computed tomography. The study included the micro-tomography analysis of 36 rabbits’ incisor extraction sockets, either left empty or filled with a collagen plug. All animals were euthanized in a staggered manner, in order to address molecular, histologic, and radiographic analyses at different time-points, up to 90 days after surgery. The three-dimensional evaluation was carried out using micro-computed tomography technology on excised bone blocks including the alveolus and the contralateral bone. Both linear and volumetric measures were recorded: the percentage of bone volume change (ΔBV) within the region of interest was considered the primary endpoint of the study. The micro-CT analysis revealed mean volumetric changes of −58.1% ± from baseline to 3 months for the control group, and almost no bone loss for the test group, −4.6%. The sockets treated with the collagen plug showed significantly less dimensional resorption, while the natural-healing group showed an evident collapse of the alveolar bone three months after extraction surgery.

Effects of hyaluronic acid and deproteinized bovine bone mineral with 10% collagen for ridge preservation in compromised extraction sockets

BACKGROUND

The aim of this study was to evaluate the efficacy of deproteinized bovine bone mineral with 10% collagen (DBBM-C) soaked with hyaluronic acid (HA) for ridge preservation in compromised extraction sockets.

METHODS

Bilateral third, fourth premolars and first molar were hemisected, distal roots were extracted, and then combined endodontic periodontal lesion was induced in the remaining mesial roots. After 4 months, the mesial roots were extracted and the following four treatments were randomly performed: Absorbable collagen sponge (ACS), ACS soaked with HA (ACS+HA), ridge preservation with DBBM-C covered with a collagen membrane (RP), ridge preservation with DBBM-C mixed with HA and covered with a collagen membrane (RP+HA). Animals were sacrificed at 1 and 3 months following treatment. Ridge dimensional changes and bone formation were examined using microcomputed tomography, histology, and histomorphometry.

RESULTS

At 1 month, ridge width was significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups, while the highest proportion of mineralized bone was observed in ACS+HA group. At 3 months, ridge width remained significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups. ACS+HA and RP+HA treatments featured the highest proportion of mineralized bone and bone volume density compared with the other groups. No statistical difference was observed between ACS+HA and RP+HA treatments.

CONCLUSIONS

Ridge preservation with the mixture DBBM-C/HA prevented dimensional shrinkage and improved bone formation in compromised extraction sockets at 1 and 3 months.

Thrombocytopenia-Absent Radius (TAR): Case report of dental implant and surgical treatment

Thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation in which affected individuals present reductions in the number of platelets, hypoplasia, or absence of radial bone unilaterally or bilaterally. Hematologic, skeletal, cardiac (particularly tetralogy of Fallot and septal-atrial defects), and gastrointestinal anomalies are most commonly associated with TAR syndrome. Skeletal changes result in a higher risk of dental and craniofacial trauma in patients with the syndrome. Thus, it is important for the dentist to be aware of the characteristics of TAR syndrome and its clinical management for better care of these patients. The objective of this study is to describe a case report of a 26-year-old patient with TAR syndrome with a history of trauma and root fracture of tooth 11 and alveolar bone ridge. During anamnesis, root fractures requiring the extraction of the 11 tooth, alveolar bone ridge fracture in the adjacent region, and dental trauma were observed. A hematological evaluation and blood and radiological examinations were performed. Osseointegrated implant was performed using the guided surgery and flapless technique, as well as prosthetic rehabilitation in the affected region. This report discusses the importance of careful planning, such as the use of incisions and conservative surgery, techniques for alveolar ridge preservation, gingival manipulation, and prosthesis confection. The patient was attended by a hematologist throughout the treatment.

Key words:TAR syndrome, absent radii and thrombocytopenia, dental implants, oral surgery.

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing

Background: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing. Methods: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months. Results: The crestal gingiva was significantly thinner in group ARP (−1.16 mm) compared to group SH (p < 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: −0.75 mm; palatal: −0.85 mm) compared to group SH (p < 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups (p > 0.05). Conclusions: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups.

Evaluation of Poly Lactic-co-Glycolic Acid-Coated β-Tricalcium Phosphate Bone Substitute as a Graft Material for Ridge Preservation after Tooth Extraction in Dog Mandible: A Comparative Study with Conventional β-Tricalcium Phosphate Granules

This study aims to evaluate the safety and efficacy of a poly lactic-co-glycolic acid (PLGA)-coated β-tricalcium phosphate (β-TCP) with N-methyl-2-pyrrolidone (NMP) liquid activator (PLGA/β-TCP) on alveolar ridge preservation after tooth extraction in dog mandible. Thirty-two extraction sites were prepared in eight dog mandibles. A distal root of the mandibular premolar was extracted and randomly grafted with one of the following bone substitutes: (1) PLGA/β-TCP, (2) β-TCP, or (3) left empty as a control, and wounds were closed with keratinized mucosa graft. Post-operative wound healing was observed and scored to evaluate safety. After 12 and 24 weeks, the bone regeneration was evaluated with micro-computed tomography (CT) images and histomorphometric analyses. Gingival epithelization progressed over time without complication or infection. Micro-CT images and histological observation revealed that both PLGA/β-TCP and β-TCP granules supported sufficient new bone formation. Although bone formation and substrate resorption were delayed slightly with the PLGA and the NMP-containing plasticizer as compared to those treated with conventional β-TCP, it can be concluded that the PLGA and the NMP-containing plasticizer that facilitated the in situ hardening properties of the material had no negative influence on the biocompatibility of the material.

Comparison of histomorphometry and microCT after sinus augmentation using xenografts of different particle sizes in rabbits

PURPOSE

The aim of the present experiment was to compare the data on new bone formation measured histologically and microtomographically in maxillary sinuses augmented with a xenograft with higher density and higher mineral content compared with the natural bone. The hypothesis was that histomorphometric and micro-computed tomography (microCT) analyses do not yield similar outcomes when a xenograft with higher density and mineral content compared with the natural bone is used.

METHODS

In 18 rabbits, the maxillary sinus was augmented bilaterally using deproteinized bovine bone mineral (DBBM) xenograft granules of either 0.125-1 mm or 1-2 mm of dimensions. The rabbits were euthanized after 2, 4, and 8 weeks of healing. Comparisons were performed between microCT and histological analyses.

RESULTS

After 2 weeks of healing, higher contents of bone were found at the histological compared with the microCT analyses in both sinuses, especially in the middle regions of the grafted sinus. Between 2 and 8 weeks of healing, new bone increased of about 21% at the histological analyses while, at the microCT, increased only about 4%. In the same period, the xenograft proportion decreased from 51.6 ± 4.9 to 45.3 ± 3.3% at the histological analyses while, at the microCT, the xenograft appeared to increase in percentages.

CONCLUSION

Histological and microCT analyses yielded different outcomes when a xenograft with higher density and higher mineral content compared with the natural bone was used.

Histological and micro-computed tomography evaluations of newly formed bone after maxillary sinus augmentation using a xenograft with similar density and mineral content of bone: An experimental study in rabbits

The objective of this study was to evaluate possible differences in the assessment of bone formation between histological and micro-computed tomography (CT) analyses in maxillary sinuses augmented with a xenograft with similar density and mineral content of bone. A collagen membrane was placed subjacent the elevated sinus mucosa at the test sites of 18 rabbits, and the elevated spaces were filled with xenograft. The antrostomy was covered with collagen membranes, bilaterally. Six rabbits per group were sacrificed after 2, 4, and 8 weeks of healing. Biopsies were retrieved and scanned in a high-resolution micro-CT at two different gray thresholds. Histological assessments were subsequently performed. At the histological analyses, bone increased over time, from 7.5 ± 2.4% to 27.0 ± 5.3%, between 2 and 8 weeks of healing. The highest content of bone was found close to the sinus bone walls, whereas the middle regions contained lower amounts. At the micro-CT analyses, discrepancies were found in bone content percentages compared with the histological analyses, especially after 2 weeks of healing and within the middle regions of the sinus, in which new bone was ~15-22% at the micro-CT analyses and only 1.6% at the histological evaluation. The outcomes of a micro-CT analysis performed in an early phase of healing may be altered when a resorbable bone substitute with similar density and mineral content of bone is applied.

A novel methodological approach using superimposed Micro-CT and STL images to analyze hard and soft tissue volume in immediate and delayed implants with different cervical designs

OBJECTIVES

To study the hard and soft tissue volume after placing immediate (IMI) or delayed implants (DLI) with a triangular coronal macro-design (Test/T) or a conventional cylindrical design (Control/C).

MATERIAL AND METHODS

T/C implants were inserted in healed ridges or in fresh extraction sockets of eight beagle dogs. Biopsies were processed for Micro-CT analysis and dental stone casts were optically scanned to obtain STL files revealing the soft tissue contours at 12 weeks. Image analysis software was utilized to match common landmarks superimposing the two sets of data. Three distinct volumes were calculated; buccal bone volume (B-BV), soft tissue volume below the implant shoulder (EC-STV), and the soft tissue volume above the implant shoulder (SC-STV). Using linear measurements, the soft tissue height (STH), the mucosal thickness (MT-IS), and the distance from the implant shoulder to the bone crest (I-BC) were assessed in the digital images and in conventional histology to assess the concordance, reproducibility, and reliability.

RESULTS

There were no significant differences between test and control implants regarding the buccal bone volume, although test implants had greater B-BV in all locations except for PM2. The soft tissue volume was similar at T/C implants. The surgical approach influenced the distribution of the total tissue volume. In the IMI, a low position of the bone crest was correlated with low values of B-BV, SC-STV, MT-IS, and STH. Linear measurements showed a high correlation between the histology and digital measurements and high inter and intra examiner agreement.

CONCLUSION

The superimposition of Micro-CT/STL allowed the analysis of soft and hard tissue volumes. Reduction of the implant buccal aspect resulted in nonsignificant higher bone volume although similar soft tissue volume while the surgical approach influenced soft tissue response.