Adequate alveolar bone volume is a prerequisite for predictable and long-term success in dental implant therapy. Physiological post-extraction remodeling frequently results in horizontal and vertical ridge deficiencies, which may compromise optimal implant placement. Guided bone regeneration (GBR) has become a cornerstone procedure in implant dentistry, with clinical outcomes largely influenced by the biological and mechanical characteristics of grafting materials. Different bone grafts and their combinations are currently clinically applicable, each exhibiting distinct osteogenic, osteoinductive, and osteoconductive properties, as well as varying resorption profiles and volumetric stability. This narrative review aims to analyze the biological principles of alveolar ridge augmentation, compare the properties of commonly used graft materials, evaluate clinical outcomes, and discuss emerging regenerative strategies. Literature published between 2000 and 2025 was assessed to synthesize current evidence regarding graft integration, bone formation, desorption dynamics, and clinical indications. Autogenous bone remains the gold standard due to its combined osteogenic, osteoinductive, and osteoconductive potential; however, its limitations have driven the development of alternative materials, including allografts, xenografts, alloplastic substitutes, demineralized tooth matrices, platelet concentrates, and customized scaffolds. While no single material is universally ideal, appropriate selection based on defect characteristics and clinical objectives is essential for predictable outcomes. Future research should prioritize long-term comparative trials, biomaterial standardization, and biologically enhanced regenerative approaches.

Background/Aim. Parathyroid hyperplasia (PHP) is defined as an absolute increase in the mass of parenchymal cells of the parathyroid gland. PHP is classified as primary, secondary and tertiary. The enlargement of parathyroid glands (PG) is usually asymmetric, resulting in a ?dominant? gland. In order to confirm the diagnosis, at least two glands should be examined histologically. Subtotal parathyroidectomy, i.e. removal of the three PG and leaving a small remnant of the forth, is the treatment of choice. High percent of PHP recurrence imposes the need for preoperative high sensitivity localizing procedures. Parathyroid scintigraphy localizes about 60% of hyperplastic glands. The aim of this study was to correlate findings of subtraction parathyroid scintigraphy (SPS) with weight, pathohistologic finding and oxyphil cell (OC) content of PG in patients with primary, secondary and tertiary parathyroid hyperplasia. Methods. Twenty-seven patients with primary/secondary PHP underwent SPS before surgery. Scintigraphic results were graded from 1-5, in relation to the degree of uptake. SPS graded 3, 4 and 5 were considered positive. The number and weight of operated PG were evaluated macroscopically. Pathohistologic and cellular types were defined on standard stained hematoxylin-eosin slides. OC content was defined as a percent of OC and graded from 1 to 3: grade 1 < 10%, grade 2 ? 10% and grade 3 ? 20% of OC. Results. SPS localized dominant gland in all patients with sensitivity 100%, and 51 from 73 hyperplastic PG, with sensitivity per gland of 70%. PG weighed 0.1 g to 6.7 g (median 1 g). A significant positive correlation (p < 0.0001) was found between the SPS results and PG weight. A significant positive correlation was found between PG weight and OC content (p = 0.0002). An insignificant correlation was found between SPS and OC content. Thirty-eight PG had < 10% of OC, 32 PG had < 10% and 3 PG had ? 20% of OC. Four patients had diffuse PHP and 23 patients nodular PHP. There was no statistically significant difference in SPS results compared to hyperplasia type, and between OC content and hyperplasia type. A significant positive correlation (p = 0.05) was found between PG weight and hyperplasia type. Conclusion. A high positive correlation was found between SPS results and PG weight, PG weight and OC content and PG weight and hyperplasia type. Between SPS results and OC content, and between SPS results and hyperplasia type, an insignificant correlation was found. Our results showed that SPS is a reliable and very sensitive diagnostic tool in detecting abnormal PG in parathyroid hyperplasia, reaching 100% sensitivity in detecting a ?dominant gland? and sensitivity per localized gland of 70%. Causes that affect increased uptake of liposolubile Tc99m radiopharmaceuticals (RF) in the hyperfunctional PG tissue and conditions which prevent RF admission into the PG cells still remain to be accurately and precisely determined.

Background/Aim. Ultrasonography is a cheap, easily available and convenient method for diagnosis. The aims of this study were: to determine the utility of ultrasonography for preoperative identification and localization of enlarged parathyroid glands (PTG) in patients with different forms of hyperparathyroidism (HPT); to examine the frequency of PTG detection in patients previously non-suspected for HPT but having symptoms relevant to the disease; to determine sensitivity and positive predictive value (PPV) of ultrasonography for identification of PTG in HPT and to compare obtained results with those obtained by scintigraphy. Methods. This investigation was designed as a retrospective?prospective study. The total number of patients undergoing ultrasonography prior to surgery was 179 and the number of those subjected to scintigraphy, mostly by the 201Tl/99mTc method, was 112. The patients (52 male, 128 female) were divided into the following four groups: group A ? patients with primary (p)HPT (n = 78); group B ? patients with secondary (s)HPT (n = 47); group C ? patients with tertiary (t)HPT (n = 13); group D ? patients with unrecognized (u)HPT, but with anamnestic data implying the disease (n = 42). High resolution ultrasonography was performed by a single experienced observer. Diagnosis of HPT was based on characteristic clinical and biochemical parameters. Final proof of HPT diagnosis was surgery followed by histopathological examination. Results. Ultrasonography detected enlarged PTG in 93.85% of total patients, whereas scintigraphy uncovered 75.89% of positive cases (p < 0.05). The total number of positive PTG detected by ultrasonography was 211 vs 225 detected by surgery (sensitivity ? 95.9%; PPV ? 99.4%). Histopathology confirmed the predominance of adenoma in the A and D groups in comparison with the B group of patients having PTG hyperplasia. The group C was characterized by the presence of adenomas in hyperplastic PTG. The mean size of PTG measured by ultrasonography was 17.59 ? 8.0 mm (n = 164) vs 18.36 ? 8.54 mm (n = 179) measured after surgery. Ultrasonography proved itself as an accurate technique in all HPT groups, regarding its high sensitivity (range 93.6?100%) and PPV (95.6?100%). In contrast, scintigraphy was shown to be less reliable, especially in the sPTH group (sensitivity: 51.7%; PPV: 78.4%). Conclusion. Ultrasonography is more sensitive and accurate method for pre-operative localization of PTG in comparison with 201Tl/99mTc scintigraphy. It can be also efficiently used for detection of PTG and diagnosis of HPT in patients previously not suspected for this disease.