Treatment of the grossly Treatment of the grossly resorbed mandibular ridgeresorbed mandibular ridge

Mohammad Al SayedMohammad Al Sayed

22/4/200822/4/2008

Gross mandibular atrophyGross mandibular atrophy::

Multifactorial biomechanical disease Multifactorial biomechanical disease resulting from a combination of anatomic, resulting from a combination of anatomic, metabolic, and mechanical determinant metabolic, and mechanical determinant varying with time from patient to patient in varying with time from patient to patient in

an infinite number of combinationsan infinite number of combinations

Causes of mandibular atrophy and Causes of mandibular atrophy and alveolar bone lossalveolar bone loss::

11..Disuse atrophyDisuse atrophy..

22..Localized excessive pressure during incising and Localized excessive pressure during incising and unilateral function under a denture unilateral function under a denture. .

33..Periodontal bone loss before extraction of the Periodontal bone loss before extraction of the teeth teeth . .

44..HyperparathyroidismHyperparathyroidism..

55..HypogondismHypogondism..

66..Nutritional deficiencies and tissue resistance to Nutritional deficiencies and tissue resistance to stress stress..

Clinical factors affecting bone Clinical factors affecting bone resorptionresorption::

11..Anatomic factorsAnatomic factors As the size and shape of the ridge, the ridge As the size and shape of the ridge, the ridge

relations, and the thickness and character of relations, and the thickness and character of mucosal covering mucosal covering

22..Metabolic factorsMetabolic factors As age, Sex, nutrition, hormonal balance, As age, Sex, nutrition, hormonal balance,

osteoporosis osteoporosis..33..Functional factorsFunctional factors

Frequency, direction, and amount of force Frequency, direction, and amount of force applied to bone applied to bone..

44..Prosthetic factorsProsthetic factors The type of denture base, the form and type of The type of denture base, the form and type of

teeth, the interocclusal distance and etc teeth, the interocclusal distance and etc . .

Problems as a result of extensive Problems as a result of extensive changes in the facial and intraoral changes in the facial and intraoral tissues following the loss of permanent tissues following the loss of permanent dentitiondentition::

11..Morphological changesMorphological changes : :

caused by either reduction in facial tissue caused by either reduction in facial tissue support due to resorption and support due to resorption and

remodeling of the alveolar tissues remodeling of the alveolar tissues . .

22..Neuromuscular changesNeuromuscular changes::

Resulting in indefinite occlusal positionsResulting in indefinite occlusal positions

Facial morphological changesFacial morphological changes::

Changes in facial contourChanges in facial contour

Facial supportFacial support

Rest facial heightRest facial height

Changes in facial musclesChanges in facial muscles

Loss of support for the facial musculatureLoss of support for the facial musculature

Muscle attachmentMuscle attachment

Changes in temporomandibular jointsChanges in temporomandibular joints..

Intraoral morphological changesIntraoral morphological changes::

--Apparent loss of sulcus width and depthApparent loss of sulcus width and depth

--Muscle attachmentMuscle attachment

--Bony prominenceBony prominence

11 . .Sharp, spiny ridgesSharp, spiny ridges

22 . .Uneven alveolar boneUneven alveolar bone

33 . .Prominent mylohyoid and internal Prominent mylohyoid and internal oblique ridge oblique ridge..

44 . .Sharp mentalis eminenceSharp mentalis eminence..

55..Enlarged genial tubercleEnlarged genial tubercle . .

The problem of the Mandibular The problem of the Mandibular reduced residual ridgereduced residual ridge::

11..The average maxillary denture bearing area is 23cm², The average maxillary denture bearing area is 23cm², while the average mandibular denture bearing area is while the average mandibular denture bearing area is only 12cm² and the mandible is susceptible to resorption only 12cm² and the mandible is susceptible to resorption four times than the maxillafour times than the maxilla..

22 . .The surface contour of the resorbed ridge may prejudice The surface contour of the resorbed ridge may prejudice denture support and the superficial aspect of the denture support and the superficial aspect of the mylohyoid ridge may also be sharp, irregular, and mylohyoid ridge may also be sharp, irregular, and prominent which makes it unfavorable for support due to prominent which makes it unfavorable for support due to painful loading of the covering mobile mucosa. In cases painful loading of the covering mobile mucosa. In cases of nerve dehiscence and ridge irregularity the master of nerve dehiscence and ridge irregularity the master cast should be relieved before construction of the cast should be relieved before construction of the conventional denture base, where surgery is thought to conventional denture base, where surgery is thought to be inappropriatebe inappropriate

33 . .Lack of retention and stability of the conventional Lack of retention and stability of the conventional mandibular complete denture is commonly a complaint mandibular complete denture is commonly a complaint of patient’s with reduced residual ridges because of the of patient’s with reduced residual ridges because of the unfavorable flat ridge from which does not provide any unfavorable flat ridge from which does not provide any resistance to anteroposterior or lateral movements. resistance to anteroposterior or lateral movements. Chronic mucosal irritation, discomfort, and the inability to Chronic mucosal irritation, discomfort, and the inability to properly masticate are usually attendant history findings properly masticate are usually attendant history findings as wellas well..

44 . .As a result of the reduction of the residual ridge, the floor As a result of the reduction of the residual ridge, the floor of the mouth becomes relatively superficialof the mouth becomes relatively superficial..

55 . .Severe mandibular atrophy will result in the genial Severe mandibular atrophy will result in the genial tubercle and attached muscle becoming sufficiently tubercle and attached muscle becoming sufficiently

superficial to interfere with the lingual flangesuperficial to interfere with the lingual flange . .66 . .On the labial surface of the anterior region several On the labial surface of the anterior region several

muscles show proximity to the crest of the ridge, muscles show proximity to the crest of the ridge, especially in badly resorbed ridges. These muscles especially in badly resorbed ridges. These muscles should not be impinged on because their action is nearly should not be impinged on because their action is nearly

at right angles to the flangeat right angles to the flange . .

77 . .The influence of the lip on lower denture stability The influence of the lip on lower denture stability becomes more critical as resorption of the ridge becomes more critical as resorption of the ridge increases or as the patient becomes older. The increases or as the patient becomes older. The lip instead of being everted as in young lip instead of being everted as in young individual becomes thinner and inclines individual becomes thinner and inclines backward into the mouthbackward into the mouth..

88 . .The large intermaxillary space that results from The large intermaxillary space that results from excessive bone loss creates prosthesis excessive bone loss creates prosthesis problems of esthetics related to loss of facial problems of esthetics related to loss of facial support, occlusion, and the patient ability to support, occlusion, and the patient ability to control the prosthesiscontrol the prosthesis..

99 . .These cases with grossly resorbed lower ridges These cases with grossly resorbed lower ridges often have the crest of the ridge at the level of often have the crest of the ridge at the level of the mental foramina, in which the nerves and the mental foramina, in which the nerves and blood vessels are impinged on easily. This blood vessels are impinged on easily. This causes paresthesia of the lower lip occurring causes paresthesia of the lower lip occurring

during masticationduring mastication..

TreatmentTreatment: :

Ideal denture supporting ridgeIdeal denture supporting ridge::11..Adequate bone support for denturesAdequate bone support for dentures..

22..Bone covered by adequate soft tissueBone covered by adequate soft tissue..33..No undercuts or hanging protuberancesNo undercuts or hanging protuberances..

44..No sharp ridgesNo sharp ridges..55..Adequate buccal and lingual sulciAdequate buccal and lingual sulci..

66..No scar bands to prevent normal seating of a dentureNo scar bands to prevent normal seating of a denture..77..No muscle fibers or frenula to interfere with the periphery No muscle fibers or frenula to interfere with the periphery

of the prosthesis of the prosthesis . .88..Satisfactory ridge relationships between the maxillae and Satisfactory ridge relationships between the maxillae and

mandible mandible . .99..No soft tissue folds, hypertrophies on the ridge or sulciNo soft tissue folds, hypertrophies on the ridge or sulci..

1010..A ridge free of neoplastic diseaseA ridge free of neoplastic disease..

11 . .Preventive prosthodonticsPreventive prosthodontics::

The greatest way to preserve the The greatest way to preserve the mandibular anterior ridge comes from the mandibular anterior ridge comes from the maintenance of one or more maintenance of one or more endodontically treated roots and the endodontically treated roots and the placement of an overdentureplacement of an overdenture..

The advantages of the overdenture over the The advantages of the overdenture over the conventional denture areconventional denture are::

The advantages of the overdenture The advantages of the overdenture over the conventional denture areover the conventional denture are::

11..The denture bearing mucosa of the The denture bearing mucosa of the residual ridges are spared abuseresidual ridges are spared abuse..

22..Maintenance of the alveolar boneMaintenance of the alveolar bone..33..Sensory feedbackSensory feedback..

44..Minimal load thresholdsMinimal load thresholds..55..Tactile sensitivity discriminationTactile sensitivity discrimination..

66..Masticatory performanceMasticatory performance..77..Reduction of Psychological traumaReduction of Psychological trauma..

22..Prosthodontic TreatmentProsthodontic Treatment::

Many techniques have been developed to deal Many techniques have been developed to deal with the problem of the compromised ridgewith the problem of the compromised ridge..

11..Principle of mucostaticsPrinciple of mucostatics..22..Using metal bases for snugness of fit of the Using metal bases for snugness of fit of the

mandibular denture mandibular denture..33..Implanting platinum cobalt magnets to increase Implanting platinum cobalt magnets to increase

mandibular denture stability mandibular denture stability . .44..The flange technique which provided greater The flange technique which provided greater

denture-bearing surface for stabilization denture-bearing surface for stabilization . .Proper coverage of all available denture-bearing Proper coverage of all available denture-bearing surface is fundamental to good denture surface is fundamental to good denture constructionconstruction..

33..Surgical managementSurgical management::

11..Enlagement of denture-bearing areasEnlagement of denture-bearing areas

a)Vestibuloplastya)Vestibuloplasty..

b)Ridge augmentationb)Ridge augmentation..

22..ImplantsImplants

a)Subperiosteala)Subperiosteal..

b)Transosseousb)Transosseous

c)Endosseousc)Endosseous..