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This study aimed to determine the reliability of three-dimensional (3D) stereophotogrammetry as a measurement instrument for evaluating soft tissue changes in the head and neck area. Twelve patients received a bilateral sagittal split osteotomy (BSSO). Test and retest 3D photographs were captured within the first three postoperative weeks, and a reference 3D photograph was capture at three months postoperatively. Distance measurements, mean and root mean square of the distance map, and volume differences were obtained. Reliability of these parameters was assessed by intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and smallest detectable change (SDC). All distance measurements had an ICC > 0.91, and the distance map parameters and volume differences showed ICCs > 0.89. The neck region presented the largest SEMs (5.09 mL) and SDC (14.1 mL) for the volume difference. In conclusion, 3D stereophotogrammetry is reliable for distance and volume measurements of soft tissues in patients after a BSSO advancement.

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OBJECTIVES: Surgical removal of squamous cell carcinoma of the tongue (SCCT) with tumour-free margin status (≥5 mm) is essential for loco-regional control. Inadequate margins (<5 mm) often indicate adjuvant treatment, which results in increased morbidity. Ultrasound (US)-guided SCCT resection may be a useful technique to achieve more adequate resection margins compared to conventional surgery. This study evaluates the application and accuracy of this technique. METHODS: Forty patients with SCCT were included in a consecutive US cohort. During surgery, the surgeon aimed for a 10-mm echographic resection margin, while the tumour border and resection plane were captured in one image. Ex-vivo US measurements of the resection specimen determined whether there was a need for an immediate re-resection. The margin status and the administration of adjuvant treatment were compared those of with a consecutive cohort of 96 tongue cancer patients who had undergone conventional surgery. A receiver operating characteristic analysis was done to assess the optimal margin of ex-vivo US measurements to detect histopathologically inadequate margins. RESULTS: In the US cohort, the frequency of free margin status was higher than in the conventional cohort (55% vs. 16%, p < 0.001), and the frequency of positive margins status (<1 mm) was lower (5% vs. 15%, respectively, p < 0.001). Adjuvant radiotherapy was halved (10% vs. 21%), and the need for re-resection was comparable (10% vs. 9%). A cut-off value of 8 mm for ex-vivo measurements prevented histopathologically inadequate margins in 76%. CONCLUSION: US-guided SCCT resections improve margin status and reduce the frequency of adjuvant radiotherapy.

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OBJECTIVES: The aim of this pre-clinical study was to evaluate the biological performance of two injectable calcium phosphate cement (CPC) composite materials containing poly(D,L-lactic-co-glycolic)acid (PLGA) microspheres with different properties in a maxillary sinus floor elevation model in sheep. MATERIALS AND METHODS: PLGA microspheres were made of either low molecular weight (~17 kDa) acid-terminated PLGA (PLGA(L-AT) ) or high molecular weight (~44 kDa) end-capped PLGA (PLGA(H-EC) ) and incorporated in CPC. Eight female Swifter sheep underwent a bilateral maxillary sinus floor elevation procedure via an extra-oral approach. All animals received both materials, alternately injected in the left and right sinus (split-mouth model) and a time point of 12 weeks was used. Analysis of biological performance was based on histology, histomorphometry, and evaluation of sequential fluorochrome labeling. RESULTS: Both types of CPC-PLGA composites showed biocompatibility and direct bone-cement contact. CPC-PLGA(L-AT) showed a significantly higher degradation distance compared to CPC-PLGA(H-EC) (1949 ± 1295 µm vs. 459 ± 267 µm; P = 0.0107). Further, CPC-PLGA(L-AT) showed significantly more bone in the region of interest (26.4 ± 10.5% vs. 8.6 ± 3.9% for PLGA(H-EC) ; P = 0.0009) and significantly less remaining CPC material (61.2 ± 17.7% vs. 81.9 ± 10.9% for PLGA(H-EC) ; P = 0.0192). CONCLUSIONS: Both CPC-PLGA(L-AT) and CPC-PLGA(H-EC) demonstrated to be safe materials for sinus floor elevation procedures in a large animal model, presenting biocompatibility and direct bone contact. In view of material performance, CPC-PLGA(L-AT) showed significantly faster degradation and a significantly higher amount of newly formed bone compared to CPC-PLGA(H-EC) .

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Preprosthetic surgery has become a routine procedure to obtain sufficient bone quantity and quality for dental implant installation in patients with an initial inadequate bone volume. Although autologous bone onlay or inlay grafting is still the preferred bone augmentation technique, a broad range of synthetic bone substitutes have been developed, for example, calcium phosphate cement (CPC). The introduction of porosity within CPC can be used to increase CPC degradation and bone ingrowth. Therefore, three different strategies to obtain porous CPCs were evaluated in this preclinical study. Instantaneously porous CPC (CPC-IP) was compared with delayed porous CPC in vitro and in vivo. CPC-IP was obtained by the creation of CO2 bubbles during setting, whereas delayed porous CPC was obtained after the degradation of incorporated poly(lactic-co-glycolic acid) (PLGA) microspheres. As an additional aspect, delayed porous CPC was created by the incorporation of either hollow or dense degradable PLGA microspheres (CPC-hPLGA and CPC-dPLGA). All CPC compositions showed appropriate clinical handling properties and an interconnected porous structure with a final porosity above 70% (v/v). In vitro degradation studies showed the gradual formation of pores and further CPC-matrix dissolution for CPCs containing PLGA microspheres (dPLGA microspheres > hPLGA microspheres). For in vivo evaluation of the CPCs, an augmentation model was used, allowing a CPC injection into a rigidly immobilized Teflon ring on the rat skull. Histological evaluation after 12 weeks of implantation showed bone formation using all three CPCs. Bone apposition reached volumetric amounts of up to 10% of the augmentation area and a maximum augmentation height of ∼1 mm. CPC-IP showed significantly more bone formation and resulted in a superior bone apposition height compared with both CPCs containing PLGA microspheres. No differences in biological performance were observed between the CPCs containing hPLGA and those containing dPLGA microspheres. Further research is necessary to enhance the bone appositional speed and amount of CPCs for bone augmentation procedures before them being used in a potential clinical setting.

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BACKGROUND: To date, no studies have been published in which histomorphometric data from a large group of patients comparing various biomaterials for sinus floor augmentation procedures were evaluated. MATERIALS AND METHODS: A meta-analysis of the English literature from January 1993 till April 2009 was carried out. Out of 147 titles, according to our criteria, 64 articles were selected for analysis describing the use of autologous bone and their alternatives, such as allogenic, xenogenic, and alloplastic materials. RESULTS: On the basis of autologous bone grafting, a reference value for total bone volume (TBV) of 63% was found. Particulation of the bone graft resulted in a general reduction of −18% in TBV. Delayed implant placement reduced the TBV with −7%. Overall TBV was 8% or 6% higher if a biopsy was, respectively, taken before 4.5 months or after 9.0 months after initial sinus augmentation surgery. Allogenic, xenogenic, alloplastic, or combinations of graft materials all resulted in a significant lower amount of TBV compared to autologous bone grafting ranging from −7% to −26%. Inventorying the effect of "biopsy time" for autologous bone, the TBV was significantly higher before 4.5 and after 9.0 months of healing time compared to period in between. Surprisingly, no significant differences in TBV with respect to "biopsy time" for bone substitutes were found. CONCLUSIONS: On the basis of the aspect of TBV autologous bone still has to be considered to be the gold standard in sinus augmentation surgery. However, the consequence of the TBV for implant survival is still unraveled yet.

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BACKGROUND: To date, no studies have been published that evaluated histomorphometric data from a large number of patients while comparing different sites and methods of autologous bone grafting in sinus floor augmentation procedures. A meta-analysis of the English literature from January 1995 till April 2009 was carried out. MATERIALS AND METHODS: PubMed search engine and the following journals were explored: Clinical Oral Implant Research, International Journal of Oral and Maxillofacial Implants, International Journal of Periodontics and Restorative Dentistry, and the Journal of Periodontology. RESULTS: Out of 147 titles, according to our criteria, 25 articles were left for analysis. The majority were prospective controlled studies (21) and 2 randomized clinical trials, 1 pilot study and 1 case series. A reference value of 47% for total bone volume (TBV) was found while using iliac bone grafting as a standard. Use of intraoral bone grafts increases the TBV, with 11% for chin bone and 14% for bone grafted from other intraoral sites. Particulation of the bone graft has a negative effect on the TBV of 18%. Surprisingly, no correlation between TBV and the time of graft healing was found. Histological section thickness seemed to be a significant variable, as every micron increase of section thickness leads to an increase of 0.4% of TBV. CONCLUSIONS: Bone grafting from the iliac crest resulted in a significantly lower TBV compared with intraoral bone grafting. However, due to the limited availability of intraoral bone to be harvested, iliac grafts still have to be considered the gold standard in augmenting the severely atrophic maxilla.

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